diff --git a/README.md b/README.md
index 09dd971682..a787f212a5 100644
--- a/README.md
+++ b/README.md
@@ -9,9 +9,9 @@ Below is an overview of the Arbitrum SDK functionality. See the [tutorials](http
 - ##### Deposit Ether Into Arbitrum
 
 ```ts
-import { getL2Network, EthBridger } from '@arbitrum/sdk'
+import { getArbitrumNetwork, EthBridger } from '@arbitrum/sdk'
 
-const l2Network = await getL2Network(
+const l2Network = await getArbitrumNetwork(
   l2ChainID /** <-- chain id of target Arbitrum chain */
 )
 const ethBridger = new EthBridger(l2Network)
diff --git a/scripts/deployStandard.ts b/scripts/deployStandard.ts
index 78133b305e..21fb478986 100644
--- a/scripts/deployStandard.ts
+++ b/scripts/deployStandard.ts
@@ -1,11 +1,11 @@
 import { instantiateBridge } from './instantiate_bridge'
 import dotenv from 'dotenv'
 import args from './getCLargs'
-import { constants, BigNumber, utils } from 'ethers'
+import { constants, BigNumber } from 'ethers'
+import { ZeroAddress, formatEther } from 'ethers-v6'
 import { MultiCaller } from '../src'
 import axios from 'axios'
 import prompt from 'prompts'
-import { ZeroAddress } from 'ethers-v6'
 dotenv.config()
 
 const privKey = process.env.PRIVKEY as string
@@ -156,10 +156,10 @@ const main = async () => {
     const fee = price.mul(gasNeeded)
     if (fee.gt(walletBal)) {
       console.log(
-        `An estimated ${utils.formatEther(
-          fee
-        )} ether is needed for deposit; you only have ${utils.formatEther(
-          walletBal
+        `An estimated ${formatEther(
+          fee.toHexString()
+        )} ether is needed for deposit; you only have ${formatEther(
+          walletBal.toHexString()
         )} ether. Will try depositing anyway:`
       )
     }
diff --git a/scripts/genNetwork.ts b/scripts/genNetwork.ts
index 7dbb1ce2fd..d0b7fdff45 100644
--- a/scripts/genNetwork.ts
+++ b/scripts/genNetwork.ts
@@ -2,10 +2,14 @@ import * as dotenv from 'dotenv'
 dotenv.config()
 import { execSync } from 'child_process'
 import * as fs from 'fs'
-import { L2Network } from '../src'
-import { ARB_MINIMUM_BLOCK_TIME_IN_SECONDS } from '../src/lib/dataEntities/constants'
+
 import { IERC20Bridge__factory } from '../src/lib/abi/factories/IERC20Bridge__factory'
 import { ethers } from 'ethers'
+import {
+  L2Network,
+  ArbitrumNetwork,
+  mapL2NetworkToArbitrumNetwork,
+} from '../src/lib/dataEntities/networks'
 
 const isTestingOrbitChains = process.env.ORBIT_TEST === '1'
 
@@ -39,24 +43,29 @@ async function patchNetworks(
   l2Network: L2Network,
   l3Network: L2Network | undefined,
   l2Provider: ethers.providers.Provider | undefined
-) {
-  l2Network.parentChainId = (l2Network as any).partnerChainID
-  l2Network.blockTime = ARB_MINIMUM_BLOCK_TIME_IN_SECONDS
+): Promise<{
+  patchedL2Network: ArbitrumNetwork
+  patchedL3Network?: ArbitrumNetwork
+}> {
+  const patchedL2Network = mapL2NetworkToArbitrumNetwork(l2Network)
 
   // native token for l3
   if (l3Network && l2Provider) {
-    l3Network.parentChainId = (l3Network as any).partnerChainID
-    l3Network.blockTime = ARB_MINIMUM_BLOCK_TIME_IN_SECONDS
+    const patchedL3Network = mapL2NetworkToArbitrumNetwork(l3Network)
 
     try {
-      l3Network.nativeToken = await IERC20Bridge__factory.connect(
+      patchedL3Network.nativeToken = await IERC20Bridge__factory.connect(
         l3Network.ethBridge.bridge,
         l2Provider
       ).nativeToken()
     } catch (e) {
       // l3 network doesn't have a native token
     }
+
+    return { patchedL2Network, patchedL3Network }
   }
+
+  return { patchedL2Network }
 }
 
 async function main() {
@@ -66,17 +75,24 @@ async function main() {
 
   if (isTestingOrbitChains) {
     const { l2Network: l3Network } = getLocalNetworksFromContainer('l2l3')
-    await patchNetworks(
+    const { patchedL2Network, patchedL3Network } = await patchNetworks(
       output.l2Network,
       l3Network,
       new ethers.providers.JsonRpcProvider(process.env['ARB_URL'])
     )
+
     output = {
-      l1Network: output.l2Network,
-      l2Network: l3Network,
+      l1Network: patchedL2Network,
+      l2Network: patchedL3Network,
     }
   } else {
-    await patchNetworks(output.l2Network, undefined, undefined)
+    const { patchedL2Network } = await patchNetworks(
+      output.l2Network,
+      undefined,
+      undefined
+    )
+
+    output.l2Network = patchedL2Network
   }
 
   fs.writeFileSync('localNetwork.json', JSON.stringify(output, null, 2))
diff --git a/scripts/instantiate_bridge.ts b/scripts/instantiate_bridge.ts
index af752bc640..747a81e8b6 100644
--- a/scripts/instantiate_bridge.ts
+++ b/scripts/instantiate_bridge.ts
@@ -23,14 +23,11 @@ import dotenv from 'dotenv'
 import args from './getCLargs'
 import { EthBridger, InboxTools, Erc20Bridger } from '../src'
 import {
-  l1Networks,
-  l2Networks,
-  L1Network,
-  L2Network,
+  ArbitrumNetwork,
+  getArbitrumNetwork,
 } from '../src/lib/dataEntities/networks'
 import { Signer } from 'ethers'
 import { AdminErc20Bridger } from '../src/lib/assetBridger/erc20Bridger'
-import { isDefined } from '../src/lib/utils/lib'
 
 dotenv.config()
 
@@ -39,19 +36,18 @@ const ethKey = process.env['ETH_KEY'] as string
 
 const defaultNetworkId = 421614
 
-export const instantiateBridge = (
+export const instantiateBridge = async (
   l1PkParam?: string,
   l2PkParam?: string
-): {
-  l1Network: L1Network
-  l2Network: L2Network
+): Promise<{
+  l2Network: ArbitrumNetwork
   l1Signer: Signer
   l2Signer: Signer
   erc20Bridger: Erc20Bridger
   ethBridger: EthBridger
   adminErc20Bridger: AdminErc20Bridger
   inboxTools: InboxTools
-} => {
+}> => {
   if (!l1PkParam && !ethKey) {
     throw new Error('need ARB_KEY var')
   }
@@ -68,21 +64,8 @@ export const instantiateBridge = (
 
     l2NetworkID = defaultNetworkId
   }
-  const isL1 = isDefined(l1Networks[l2NetworkID])
-  const isL2 = isDefined(l2Networks[l2NetworkID])
-  if (!isL1 && !isL2) {
-    throw new Error(`Unrecognized network ID: ${l2NetworkID}`)
-  }
-  if (!isL2) {
-    throw new Error(`Tests must specify an L2 network ID: ${l2NetworkID}`)
-  }
 
-  const l2Network = l2Networks[l2NetworkID]
-  const l1Network = l1Networks[l2Network.parentChainId]
-
-  if (!l1Network) {
-    throw new Error(`Unrecognised parent chain id: ${l2Network.parentChainId}`)
-  }
+  const l2Network = await getArbitrumNetwork(l2NetworkID)
 
   const l1Rpc = (() => {
     if (l2NetworkID === 42161) return process.env['MAINNET_RPC'] as string
@@ -138,7 +121,6 @@ export const instantiateBridge = (
   const inboxTools = new InboxTools(l1Signer, l2Network)
 
   return {
-    l1Network,
     l2Network,
     l1Signer,
     l2Signer,
diff --git a/scripts/sendL2SignedMsg.ts b/scripts/sendL2SignedMsg.ts
index d117247518..08ccc8966f 100644
--- a/scripts/sendL2SignedMsg.ts
+++ b/scripts/sendL2SignedMsg.ts
@@ -18,11 +18,11 @@
 
 import { BigNumber } from 'ethers'
 import { InboxTools } from '../src/lib/inbox/inbox'
-import { getL2Network } from '../src/lib/dataEntities/networks'
+import { getArbitrumNetwork } from '../src/lib/dataEntities/networks'
 import { testSetup } from '../scripts/testSetup'
 const sendSignedMsg = async () => {
   const { l1Deployer, l2Deployer } = await testSetup()
-  const l2Network = await getL2Network(await l2Deployer.getChainId())
+  const l2Network = await getArbitrumNetwork(await l2Deployer.getChainId())
   const inbox = new InboxTools(l1Deployer, l2Network)
   const message = {
     to: await l2Deployer.getAddress(),
diff --git a/scripts/testSetup.ts b/scripts/testSetup.ts
index 97c0ca3638..a7a05d05c9 100644
--- a/scripts/testSetup.ts
+++ b/scripts/testSetup.ts
@@ -23,11 +23,11 @@ import dotenv from 'dotenv'
 
 import { EthBridger, InboxTools, Erc20Bridger } from '../src'
 import {
-  L1Network,
+  L2Network,
   ArbitrumNetwork,
-  getL1Network,
+  mapL2NetworkToArbitrumNetwork,
   getArbitrumNetwork,
-  addCustomNetwork,
+  addCustomArbitrumNetwork,
 } from '../src/lib/dataEntities/networks'
 import { Signer } from 'ethers'
 import { AdminErc20Bridger } from '../src/lib/assetBridger/erc20Bridger'
@@ -72,7 +72,6 @@ export const getSigner = (provider: JsonRpcProvider, key?: string) => {
 }
 
 export const testSetup = async (): Promise<{
-  parentChain: L1Network | ArbitrumNetwork
   childChain: ArbitrumNetwork
   parentSigner: Signer
   childSigner: Signer
@@ -95,53 +94,18 @@ export const testSetup = async (): Promise<{
   const parentSigner = seed.connect(ethProvider)
   const childSigner = seed.connect(arbProvider)
 
-  let setParentChain: L1Network | ArbitrumNetwork,
-    setChildChain: ArbitrumNetwork
+  let setChildChain: ArbitrumNetwork
+
   try {
-    const l1Network = isTestingOrbitChains
-      ? await getArbitrumNetwork(parentDeployer)
-      : await getL1Network(parentDeployer)
     const l2Network = await getArbitrumNetwork(childDeployer)
-    setParentChain = l1Network
     setChildChain = l2Network
   } catch (err) {
     // the networks havent been added yet
-
     // check if theres an existing network available
-    const localNetworkFile = getLocalNetworksFromFile()
-
-    const { l1Network: parentChain, l2Network: childChain } = localNetworkFile
-
-    if (isTestingOrbitChains) {
-      const _parentChain = parentChain as ArbitrumNetwork
-      const ethLocal: L1Network = {
-        blockTime: 10,
-        chainID: _parentChain.parentChainId,
-        isCustom: true,
-        name: 'EthLocal',
-        isArbitrum: false,
-      }
-
-      addCustomNetwork({
-        customL1Network: ethLocal,
-        customArbitrumNetwork: _parentChain,
-      })
-
-      addCustomNetwork({
-        customArbitrumNetwork: childChain,
-      })
-
-      setParentChain = parentChain
-      setChildChain = childChain
-    } else {
-      addCustomNetwork({
-        customL1Network: parentChain as L1Network,
-        customArbitrumNetwork: childChain,
-      })
-
-      setParentChain = parentChain
-      setChildChain = childChain
-    }
+    const { l2Network: childChain } = getLocalNetworksFromFile()
+
+    addCustomArbitrumNetwork(childChain)
+    setChildChain = childChain
   }
 
   const erc20Bridger = new Erc20Bridger(setChildChain)
@@ -160,7 +124,6 @@ export const testSetup = async (): Promise<{
     childSigner,
     parentProvider: ethProvider,
     childProvider: arbProvider,
-    parentChain: setParentChain,
     childChain: setChildChain,
     erc20Bridger,
     adminErc20Bridger,
@@ -172,7 +135,6 @@ export const testSetup = async (): Promise<{
 }
 
 export function getLocalNetworksFromFile(): {
-  l1Network: L1Network | ArbitrumNetwork
   l2Network: ArbitrumNetwork
 } {
   const pathToLocalNetworkFile = path.join(__dirname, '..', 'localNetwork.json')
@@ -180,5 +142,9 @@ export function getLocalNetworksFromFile(): {
     throw new ArbSdkError('localNetwork.json not found, must gen:network first')
   }
   const localNetworksFile = fs.readFileSync(pathToLocalNetworkFile, 'utf8')
-  return JSON.parse(localNetworksFile)
+  const localL2: L2Network = JSON.parse(localNetworksFile).l2Network
+
+  return {
+    l2Network: mapL2NetworkToArbitrumNetwork(localL2),
+  }
 }
diff --git a/src/index.ts b/src/index.ts
index c0c82efc0e..9ab26c544b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -43,13 +43,9 @@ export { ParentToChildMessageGasEstimator } from './lib/message/ParentToChildMes
 export { argSerializerConstructor } from './lib/utils/byte_serialize_params'
 export { CallInput, MultiCaller } from './lib/utils/multicall'
 export {
-  L1Networks,
-  L2Networks,
-  L1Network,
-  L2Network,
-  getL1Network,
-  getL2Network,
-  addCustomNetwork,
+  ArbitrumNetwork,
+  getArbitrumNetwork,
+  addCustomArbitrumNetwork,
   addDefaultLocalNetwork,
   getChildrenForNetwork,
 } from './lib/dataEntities/networks'
diff --git a/src/lib/assetBridger/assetBridger.ts b/src/lib/assetBridger/assetBridger.ts
index bc3f74bcd8..b803e3dc31 100644
--- a/src/lib/assetBridger/assetBridger.ts
+++ b/src/lib/assetBridger/assetBridger.ts
@@ -20,11 +20,7 @@ import { ZeroAddress } from 'ethers-v6'
 import { ParentContractTransaction } from '../message/ParentTransaction'
 import { ChildContractTransaction } from '../message/ChildTransaction'
 
-import {
-  L1Network,
-  ArbitrumNetwork,
-  getParentForNetwork,
-} from '../dataEntities/networks'
+import { ArbitrumNetwork } from '../dataEntities/networks'
 import {
   SignerOrProvider,
   SignerProviderUtils,
@@ -34,11 +30,6 @@ import {
  * Base for bridging assets from parent-to-child and back
  */
 export abstract class AssetBridger<DepositParams, WithdrawParams> {
-  /**
-   * Parent chain for the given Arbitrum chain, can be an L1 or an L2
-   */
-  public readonly parentChain: L1Network | ArbitrumNetwork
-
   /**
    * In case of a chain that uses ETH as its native/gas token, this is either `undefined` or the zero address
    *
@@ -47,7 +38,6 @@ export abstract class AssetBridger<DepositParams, WithdrawParams> {
   public readonly nativeToken?: string
 
   public constructor(public readonly childChain: ArbitrumNetwork) {
-    this.parentChain = getParentForNetwork(childChain)
     this.nativeToken = childChain.nativeToken
   }
 
@@ -56,7 +46,10 @@ export abstract class AssetBridger<DepositParams, WithdrawParams> {
    * @param sop
    */
   protected async checkParentChain(sop: SignerOrProvider): Promise<void> {
-    await SignerProviderUtils.checkNetworkMatches(sop, this.parentChain.chainID)
+    await SignerProviderUtils.checkNetworkMatches(
+      sop,
+      this.childChain.parentChainId
+    )
   }
 
   /**
@@ -64,7 +57,7 @@ export abstract class AssetBridger<DepositParams, WithdrawParams> {
    * @param sop
    */
   protected async checkChildChain(sop: SignerOrProvider): Promise<void> {
-    await SignerProviderUtils.checkNetworkMatches(sop, this.childChain.chainID)
+    await SignerProviderUtils.checkNetworkMatches(sop, this.childChain.chainId)
   }
 
   /**
diff --git a/src/lib/assetBridger/erc20Bridger.ts b/src/lib/assetBridger/erc20Bridger.ts
index 87e452b07f..f787b00365 100644
--- a/src/lib/assetBridger/erc20Bridger.ts
+++ b/src/lib/assetBridger/erc20Bridger.ts
@@ -66,7 +66,7 @@ import {
   ChildToParentTransactionRequest,
   ParentToChildTransactionRequest,
 } from '../dataEntities/transactionRequest'
-import { defaultAbiCoder } from 'ethers/lib/utils'
+import { AbiCoder } from 'ethers-v6'
 import { OmitTyped, RequiredPick } from '../utils/types'
 import { RetryableDataTools } from '../dataEntities/retryableData'
 import { EventArgs } from '../dataEntities/event'
@@ -595,26 +595,29 @@ export class Erc20Bridger extends AssetBridger<
     depositParams: OmitTyped<ParentToChildMessageGasParams, 'deposit'>
   ) {
     if (!this.nativeTokenIsEth) {
-      return defaultAbiCoder.encode(
+      return AbiCoder.defaultAbiCoder().encode(
         ['uint256', 'bytes', 'uint256'],
         [
           // maxSubmissionCost
-          depositParams.maxSubmissionCost, // will be zero
+          BigInt(depositParams.maxSubmissionCost.toHexString()), // will be zero
           // callHookData
           '0x',
           // nativeTokenTotalFee
-          depositParams.gasLimit
-            .mul(depositParams.maxFeePerGas)
-            .add(depositParams.maxSubmissionCost), // will be zero
+          BigInt(
+            depositParams.gasLimit
+              .mul(depositParams.maxFeePerGas)
+              .add(depositParams.maxSubmissionCost)
+              .toHexString()
+          ), // will be zero
         ]
       )
     }
 
-    return defaultAbiCoder.encode(
+    return AbiCoder.defaultAbiCoder().encode(
       ['uint256', 'bytes'],
       [
         // maxSubmissionCost
-        depositParams.maxSubmissionCost,
+        BigInt(depositParams.maxSubmissionCost.toHexString()),
         // callHookData
         '0x',
       ]
diff --git a/src/lib/dataEntities/address.ts b/src/lib/dataEntities/address.ts
index 1a3361e17f..70cb3263fd 100644
--- a/src/lib/dataEntities/address.ts
+++ b/src/lib/dataEntities/address.ts
@@ -1,5 +1,4 @@
-import { getAddress } from 'ethers-v6'
-import { utils } from 'ethers'
+import { getAddress, isAddress } from 'ethers-v6'
 import { ADDRESS_ALIAS_OFFSET } from './constants'
 import { ArbSdkError } from './errors'
 
@@ -16,7 +15,7 @@ export class Address {
    * @param value A valid Ethereum address. Doesn't need to be checksum cased.
    */
   constructor(public readonly value: string) {
-    if (!utils.isAddress(value))
+    if (!isAddress(value))
       throw new ArbSdkError(`'${value}' is not a valid address`)
   }
 
diff --git a/src/lib/dataEntities/networks.ts b/src/lib/dataEntities/networks.ts
index 4af9fbb072..019015ba7b 100644
--- a/src/lib/dataEntities/networks.ts
+++ b/src/lib/dataEntities/networks.ts
@@ -16,42 +16,41 @@
 /* eslint-env node */
 ;('use strict')
 
+import { Provider } from '@ethersproject/abstract-provider'
+
 import { SignerOrProvider, SignerProviderUtils } from './signerOrProvider'
 import { ArbSdkError } from '../dataEntities/errors'
-import {
-  ARB1_NITRO_GENESIS_L2_BLOCK,
-  ARB_MINIMUM_BLOCK_TIME_IN_SECONDS,
-} from './constants'
+import { ARB1_NITRO_GENESIS_L2_BLOCK } from './constants'
 import { RollupAdminLogic__factory } from '../abi/factories/RollupAdminLogic__factory'
-
-export interface Network {
-  chainID: number
-  name: string
-  isCustom: boolean
-  /**
-   * Minimum possible block time for the chain (in seconds).
-   */
-  blockTime: number
-}
-
-/**
- * Represents an L1 chain, e.g. Ethereum Mainnet or Sepolia.
- */
-export interface L1Network extends Network {
-  isArbitrum: false
-}
+import { Prettify } from '../utils/types'
 
 /**
  * Represents an Arbitrum chain, e.g. Arbitrum One, Arbitrum Sepolia, or an L3 chain.
  */
-export interface ArbitrumNetwork extends Network {
-  tokenBridge: TokenBridge
-  ethBridge: EthBridge
+export interface ArbitrumNetwork {
+  /**
+   * Name of the chain.
+   */
+  name: string
+  /**
+   * Id of the chain.
+   */
+  chainId: number
   /**
    * Chain id of the parent chain, i.e. the chain on which this chain settles to.
    */
   parentChainId: number
-  isArbitrum: true
+  /**
+   * The core contracts
+   */
+  ethBridge: EthBridge
+  /**
+   * The token bridge contracts.
+   */
+  tokenBridge: TokenBridge
+  /**
+   * The time allowed for validators to dispute or challenge state assertions. Measured in L1 blocks.
+   */
   confirmPeriodBlocks: number
   /**
    * Represents how long a retryable ticket lasts for before it expires (in seconds). Defaults to 7 days.
@@ -63,8 +62,26 @@ export interface ArbitrumNetwork extends Network {
    * In case of a chain that uses an ERC-20 token from the parent chain as its native/gas token, this is the address of said token on the parent chain
    */
   nativeToken?: string
+  /**
+   * Whether or not the chain was registered by the user.
+   */
+  isCustom: boolean
 }
 
+/**
+ * This type is only here for when you want to achieve backwards compatibility between SDK v3 and v4.
+ *
+ * Please see {@link ArbitrumNetwork} for the latest type.
+ *
+ * @deprecated since v4
+ */
+export type L2Network = Prettify<
+  Omit<ArbitrumNetwork, 'chainId' | 'parentChainId'> & {
+    chainID: number
+    partnerChainID: number
+  }
+>
+
 export interface TokenBridge {
   l1GatewayRouter: string
   l2GatewayRouter: string
@@ -93,16 +110,8 @@ export interface EthBridge {
   }
 }
 
-export interface L1Networks {
-  [id: string]: L1Network
-}
-
-export interface ArbitrumNetworks {
-  [id: string]: ArbitrumNetwork
-}
-
 export interface Networks {
-  [id: string]: L1Network | ArbitrumNetwork
+  [id: string]: ArbitrumNetwork
 }
 
 const mainnetTokenBridge: TokenBridge = {
@@ -138,47 +147,17 @@ const mainnetETHBridge: EthBridge = {
  * Storage for all networks, either L1, L2 or L3.
  */
 export const networks: Networks = {
-  1: {
-    chainID: 1,
-    name: 'Mainnet',
-    blockTime: 14,
-    isCustom: false,
-    isArbitrum: false,
-  },
-  1338: {
-    chainID: 1338,
-    name: 'Hardhat_Mainnet_Fork',
-    blockTime: 1,
-    isCustom: false,
-    isArbitrum: false,
-  },
-  11155111: {
-    chainID: 11155111,
-    name: 'Sepolia',
-    blockTime: 12,
-    isCustom: false,
-    isArbitrum: false,
-  },
-  17000: {
-    chainID: 17000,
-    name: 'Holesky',
-    blockTime: 12,
-    isCustom: false,
-    isArbitrum: false,
-  },
   42161: {
-    chainID: 42161,
+    chainId: 42161,
     name: 'Arbitrum One',
     parentChainId: 1,
-    isArbitrum: true,
     tokenBridge: mainnetTokenBridge,
     ethBridge: mainnetETHBridge,
     confirmPeriodBlocks: 45818,
     isCustom: false,
-    blockTime: ARB_MINIMUM_BLOCK_TIME_IN_SECONDS,
   },
   42170: {
-    chainID: 42170,
+    chainId: 42170,
     confirmPeriodBlocks: 45818,
     ethBridge: {
       bridge: '0xC1Ebd02f738644983b6C4B2d440b8e77DdE276Bd',
@@ -187,7 +166,6 @@ export const networks: Networks = {
       rollup: '0xFb209827c58283535b744575e11953DCC4bEAD88',
       sequencerInbox: '0x211E1c4c7f1bF5351Ac850Ed10FD68CFfCF6c21b',
     },
-    isArbitrum: true,
     isCustom: false,
     name: 'Arbitrum Nova',
     parentChainId: 1,
@@ -207,10 +185,9 @@ export const networks: Networks = {
       l2Weth: '0x722E8BdD2ce80A4422E880164f2079488e115365',
       l2WethGateway: '0x7626841cB6113412F9c88D3ADC720C9FAC88D9eD',
     },
-    blockTime: ARB_MINIMUM_BLOCK_TIME_IN_SECONDS,
   },
   421614: {
-    chainID: 421614,
+    chainId: 421614,
     confirmPeriodBlocks: 20,
     ethBridge: {
       bridge: '0x38f918D0E9F1b721EDaA41302E399fa1B79333a9',
@@ -219,7 +196,6 @@ export const networks: Networks = {
       rollup: '0xd80810638dbDF9081b72C1B33c65375e807281C8',
       sequencerInbox: '0x6c97864CE4bEf387dE0b3310A44230f7E3F1be0D',
     },
-    isArbitrum: true,
     isCustom: false,
     name: 'Arbitrum Rollup Sepolia Testnet',
     parentChainId: 11155111,
@@ -239,10 +215,9 @@ export const networks: Networks = {
       l2Weth: '0x980B62Da83eFf3D4576C647993b0c1D7faf17c73',
       l2WethGateway: '0xCFB1f08A4852699a979909e22c30263ca249556D',
     },
-    blockTime: ARB_MINIMUM_BLOCK_TIME_IN_SECONDS,
   },
   23011913: {
-    chainID: 23011913,
+    chainId: 23011913,
     confirmPeriodBlocks: 20,
     ethBridge: {
       bridge: '0x35aa95ac4747D928E2Cd42FE4461F6D9d1826346',
@@ -251,7 +226,6 @@ export const networks: Networks = {
       rollup: '0x94db9E36d9336cD6F9FfcAd399dDa6Cc05299898',
       sequencerInbox: '0x00A0F15b79d1D3e5991929FaAbCF2AA65623530c',
     },
-    isArbitrum: true,
     isCustom: false,
     name: 'Stylus Testnet',
     parentChainId: 421614,
@@ -271,20 +245,19 @@ export const networks: Networks = {
       l2Weth: '0x61Dc4b961D2165623A25EB775260785fE78BD37C',
       l2WethGateway: '0x7021B4Edd9f047772242fc948441d6e0b9121175',
     },
-    blockTime: ARB_MINIMUM_BLOCK_TIME_IN_SECONDS,
   },
 }
 
 /**
  * Determines if a chain is a parent of *any* other chain. Could be an L1 or an L2 chain.
  */
-export const isParentChain = (
-  parentChainOrChainId: L1Network | ArbitrumNetwork | number
+export const isParentNetwork = (
+  parentChainOrChainId: ArbitrumNetwork | number
 ): boolean => {
   const parentChainId =
     typeof parentChainOrChainId === 'number'
       ? parentChainOrChainId
-      : parentChainOrChainId.chainID
+      : parentChainOrChainId.chainId
 
   // Check if there are any chains that have this chain as its parent chain
   return [...Object.values(l2Networks)].some(
@@ -292,150 +265,57 @@ export const isParentChain = (
   )
 }
 
-/**
- * Determines if a chain is an Arbitrum chain. Could be an L2 or an L3 chain.
- */
-const isArbitrumNetwork = (
-  chain: L1Network | ArbitrumNetwork
-): chain is ArbitrumNetwork => {
-  return chain.isArbitrum
-}
-
-/**
- * Determines if a chain is specifically an L1 chain (not L2 or L3).
- */
-export const isL1Network = (
-  chain: L1Network | ArbitrumNetwork
-): chain is L1Network => {
-  return !chain.isArbitrum
-}
-
-/**
- * Builds an object that is a list of chains filtered by the provided predicate function indexed by their chain id
- * @param filterFn - A predicate function to determine if a chain should be included.
- * @return An object with only the filtered chains.
- */
-const getChainsByType = <T extends typeof networks>(
-  filterFn: (chain: L1Network | ArbitrumNetwork) => boolean
-): T => {
-  return Object.entries(networks).reduce<typeof networks>(
-    (accumulator, [chainId, chainData]) => {
-      if (filterFn(chainData)) {
-        accumulator[chainId] = chainData
-      }
-      return accumulator
-    },
-    {}
-  ) as T
-}
-
-const getL1Chains = () => getChainsByType<L1Networks>(isL1Network)
-const getArbitrumChains = () =>
-  getChainsByType<ArbitrumNetworks>(isArbitrumNetwork)
-
-/**
- * Returns the parent chain for the given chain.
- */
-export const getParentForNetwork = (chain: L1Network | ArbitrumNetwork) => {
-  if (!isArbitrumNetwork(chain)) {
-    throw new ArbSdkError(`Chain ${chain.chainID} is not an Arbitrum chain.`)
-  }
-
-  const parentChain: L1Network | ArbitrumNetwork | undefined =
-    networks[chain.parentChainId]
-
-  if (!parentChain || !isParentChain(parentChain)) {
-    throw new ArbSdkError(
-      `Parent chain ${chain.parentChainId} not recognized for chain ${chain.chainID}.`
-    )
-  }
-
-  return parentChain
-}
+const getArbitrumChains = () => networks
 
 /**
  * Returns a list of children chains for the given chain or chain id.
  */
 export const getChildrenForNetwork = (
-  parentChainOrChainId: L1Network | ArbitrumNetwork | number
+  parentChainOrChainId: ArbitrumNetwork | number
 ): ArbitrumNetwork[] => {
   const parentChainId =
     typeof parentChainOrChainId === 'number'
       ? parentChainOrChainId
-      : parentChainOrChainId.chainID
+      : parentChainOrChainId.chainId
 
   return Object.values(getArbitrumChains()).filter(
     arbitrumChain => arbitrumChain.parentChainId === parentChainId
   )
 }
 
-/**
- * Index of *only* L1 chains that have been added.
- */
-export let l1Networks: L1Networks = getL1Chains()
-
 /**
  * Index of all Arbitrum chains that have been added.
  */
-export let l2Networks: ArbitrumNetworks = getArbitrumChains()
+export let l2Networks = getArbitrumChains()
 
 /**
- * Returns the network associated with the given Signer, Provider or chain id.
- * @note Throws if the chain is not recognized.
+ * Returns the Arbitrum chain associated with the given signer, provider or chain id.
+ *
+ * @note Throws if the chain is not an Arbitrum chain.
  */
-export const getNetwork = async (
-  signerOrProviderOrChainID: SignerOrProvider | number,
-  layer: 1 | 2
-) => {
-  const chainID = await (async () => {
-    if (typeof signerOrProviderOrChainID === 'number') {
-      return signerOrProviderOrChainID
+export const getArbitrumNetwork = async (
+  signerOrProviderOrChainId: SignerOrProvider | number
+): Promise<ArbitrumNetwork> => {
+  const chainId = await (async () => {
+    if (typeof signerOrProviderOrChainId === 'number') {
+      return signerOrProviderOrChainId
     }
     const provider = SignerProviderUtils.getProviderOrThrow(
-      signerOrProviderOrChainID
+      signerOrProviderOrChainId
     )
 
-    const { chainId } = await provider.getNetwork()
-    return chainId
+    return (await provider.getNetwork()).chainId
   })()
 
-  let network: L1Network | ArbitrumNetwork | undefined = undefined
-
-  if (layer === 1) {
-    network = getL1Chains()[chainID]
-  } else {
-    network = getArbitrumChains()[chainID]
-  }
+  const network: ArbitrumNetwork | undefined = getArbitrumChains()[chainId]
 
   if (!network) {
-    throw new ArbSdkError(`Unrecognized network ${chainID}.`)
+    throw new ArbSdkError(`Unrecognized network ${chainId}.`)
   }
 
   return network
 }
 
-/**
- * Returns the L1 chain associated with the given signer, provider or chain id.
- *
- * @note Throws if the chain is not an L1 chain.
- */
-export const getL1Network = (
-  signerOrProviderOrChainID: SignerOrProvider | number
-): Promise<L1Network> => {
-  return getNetwork(signerOrProviderOrChainID, 1) as Promise<L1Network>
-}
-
-/**
- * Returns the Arbitrum chain associated with the given signer, provider or chain id.
- *
- * @note Throws if the chain is not an Arbitrum chain.
- */
-export const getArbitrumNetwork = (
-  signerOrProviderOrChainID: SignerOrProvider | number
-): Promise<ArbitrumNetwork> => {
-  return getNetwork(signerOrProviderOrChainID, 2) as Promise<ArbitrumNetwork>
-}
-
 /**
  * Returns the addresses of all contracts that make up the ETH bridge
  * @param rollupContractAddress Address of the Rollup contract
@@ -468,82 +348,18 @@ export const getEthBridgeInformation = async (
 }
 
 /**
- * Adds any chain to the global index of networks and updates the parent/child relationships.
- */
-const addNetwork = (network: L1Network | ArbitrumNetwork) => {
-  // store the network with the rest of the networks
-  networks[network.chainID] = network
-
-  // if it's a parent chain (L1 or L2), assign it as parent to all the children
-  if (isParentChain(network)) {
-    const children = getChildrenForNetwork(network)
-
-    children.forEach(child => {
-      child.parentChainId = network.chainID
-    })
-  }
-
-  // if it's an arbitrum chain, add it to the parent's list of children
-  if (isArbitrumNetwork(network)) {
-    const parent: L1Network | ArbitrumNetwork | undefined =
-      networks[network.parentChainId]
-
-    if (!parent) {
-      throw new ArbSdkError(
-        `Network ${network.chainID}'s parent network ${network.parentChainId} is not recognized`
-      )
-    }
-  }
-
-  l1Networks = getL1Chains()
-  l2Networks = getArbitrumChains()
-}
-
-/**
- * Registers a pair of custom L1 and L2 chains, or a single custom Arbitrum chain (L2 or L3).
+ * Registers a custom Arbitrum chain (L2 or L3).
  *
- * @param customL1Network the custom L1 chain (optional)
- * @param customArbitrumNetwork the custom L2 or L3 chain
+ * @param network
  */
-export const addCustomNetwork = ({
-  customL1Network,
-  customArbitrumNetwork,
-}: {
-  customL1Network?: L1Network
-  customArbitrumNetwork: ArbitrumNetwork
-}): void => {
-  if (customL1Network) {
-    if (customL1Network.chainID !== customArbitrumNetwork.parentChainId) {
-      throw new ArbSdkError(
-        `Partner chain id for Arbitrum network ${customArbitrumNetwork.chainID} doesn't match the provided L1 network. Expected ${customL1Network.chainID} but got ${customArbitrumNetwork.parentChainId}.`
-      )
-    }
-
-    // check the if the parent chain is in any of the lists
-    if (l1Networks[customL1Network.chainID]) {
-      throw new ArbSdkError(
-        `Network ${customL1Network.chainID} already included`
-      )
-    } else if (!customL1Network.isCustom) {
-      throw new ArbSdkError(
-        `Custom network ${customL1Network.chainID} must have isCustom flag set to true`
-      )
-    }
-
-    addNetwork(customL1Network)
+export const addCustomArbitrumNetwork = (network: ArbitrumNetwork): void => {
+  if (typeof networks[network.chainId] !== 'undefined') {
+    throw new Error(`Network ${network.chainId} already included`)
   }
 
-  if (l2Networks[customArbitrumNetwork.chainID]) {
-    throw new ArbSdkError(
-      `Network ${customArbitrumNetwork.chainID} already included`
-    )
-  } else if (!customArbitrumNetwork.isCustom) {
-    throw new ArbSdkError(
-      `Custom network ${customArbitrumNetwork.chainID} must have isCustom flag set to true`
-    )
-  }
-
-  addNetwork(customArbitrumNetwork)
+  // store the network with the rest of the networks
+  networks[network.chainId] = network
+  l2Networks = getArbitrumChains()
 }
 
 /**
@@ -551,20 +367,9 @@ export const addCustomNetwork = ({
  *
  * @see {@link https://github.com/OffchainLabs/nitro}
  */
-export const addDefaultLocalNetwork = (): {
-  l1Network: L1Network
-  l2Network: ArbitrumNetwork
-} => {
-  const defaultLocalL1Network: L1Network = {
-    blockTime: 10,
-    chainID: 1337,
-    isCustom: true,
-    name: 'EthLocal',
-    isArbitrum: false,
-  }
-
+export const addDefaultLocalNetwork = (): ArbitrumNetwork => {
   const defaultLocalL2Network: ArbitrumNetwork = {
-    chainID: 412346,
+    chainId: 412346,
     confirmPeriodBlocks: 20,
     ethBridge: {
       bridge: '0x2b360A9881F21c3d7aa0Ea6cA0De2a3341d4eF3C',
@@ -573,7 +378,6 @@ export const addDefaultLocalNetwork = (): {
       rollup: '0x65a59D67Da8e710Ef9A01eCa37f83f84AEdeC416',
       sequencerInbox: '0xE7362D0787b51d8C72D504803E5B1d6DcdA89540',
     },
-    isArbitrum: true,
     isCustom: true,
     name: 'ArbLocal',
     parentChainId: 1337,
@@ -593,18 +397,11 @@ export const addDefaultLocalNetwork = (): {
       l2Weth: '0x408Da76E87511429485C32E4Ad647DD14823Fdc4',
       l2WethGateway: '0x4A2bA922052bA54e29c5417bC979Daaf7D5Fe4f4',
     },
-    blockTime: ARB_MINIMUM_BLOCK_TIME_IN_SECONDS,
   }
 
-  addCustomNetwork({
-    customL1Network: defaultLocalL1Network,
-    customArbitrumNetwork: defaultLocalL2Network,
-  })
+  addCustomArbitrumNetwork(defaultLocalL2Network)
 
-  return {
-    l1Network: defaultLocalL1Network,
-    l2Network: defaultLocalL2Network,
-  }
+  return defaultLocalL2Network
 }
 
 /**
@@ -617,7 +414,6 @@ const createNetworkStateHandler = () => {
     resetNetworksToDefault: () => {
       Object.keys(networks).forEach(key => delete networks[key])
       Object.assign(networks, JSON.parse(JSON.stringify(initialState)))
-      l1Networks = getL1Chains()
       l2Networks = getArbitrumChains()
     },
   }
@@ -629,7 +425,7 @@ export function getNitroGenesisBlock(
   const arbitrumChainId =
     typeof arbitrumChainOrChainId === 'number'
       ? arbitrumChainOrChainId
-      : arbitrumChainOrChainId.chainID
+      : arbitrumChainOrChainId.chainId
 
   // all networks except Arbitrum One started off with Nitro
   if (arbitrumChainId === 42161) {
@@ -639,13 +435,53 @@ export function getNitroGenesisBlock(
   return 0
 }
 
-const { resetNetworksToDefault } = createNetworkStateHandler()
+export async function getMulticallAddress(
+  providerOrChainId: Provider | number
+): Promise<string> {
+  const chains = [...Object.values(l2Networks)]
+
+  const chainId =
+    typeof providerOrChainId === 'number'
+      ? providerOrChainId
+      : (await providerOrChainId.getNetwork()).chainId
+  const chain = chains.find(c => c.chainId === chainId)
+
+  // The provided chain is found in the list
+  if (typeof chain !== 'undefined') {
+    // Return the address of Multicall on the chain
+    return chain.tokenBridge.l2Multicall
+  }
 
-export { resetNetworksToDefault }
-export const getChildChain = getArbitrumNetwork
+  // The provided chain is not found in the list
+  // Try to find a chain that references this chain as its parent
+  const child = chains.find(c => c.parentChainId === chainId)
 
-export {
-  ArbitrumNetwork as L2Network,
-  ArbitrumNetworks as L2Networks,
-  getArbitrumNetwork as getL2Network,
+  // No chains reference this chain as its parent
+  if (typeof child === 'undefined') {
+    throw new Error(
+      `Failed to retrieve Multicall address for chain: ${chainId}`
+    )
+  }
+
+  // Return the address of Multicall on the parent chain
+  return child.tokenBridge.l1MultiCall
 }
+
+/**
+ * Maps the old {@link L2Network} (from SDK v3) to {@link ArbitrumNetwork} (from SDK v4).
+ */
+export function mapL2NetworkToArbitrumNetwork(
+  l2Network: L2Network
+): ArbitrumNetwork {
+  return {
+    // Spread properties
+    ...l2Network,
+    // Map properties that were changed
+    chainId: l2Network.chainID,
+    parentChainId: l2Network.partnerChainID,
+  }
+}
+
+const { resetNetworksToDefault } = createNetworkStateHandler()
+
+export { resetNetworksToDefault }
diff --git a/src/lib/inbox/inbox.ts b/src/lib/inbox/inbox.ts
index a887aa9094..dcf46148bb 100644
--- a/src/lib/inbox/inbox.ts
+++ b/src/lib/inbox/inbox.ts
@@ -29,11 +29,7 @@ import { SequencerInbox__factory } from '../abi/factories/SequencerInbox__factor
 import { IInbox__factory } from '../abi/factories/IInbox__factory'
 import { RequiredPick } from '../utils/types'
 import { MessageDeliveredEvent } from '../abi/Bridge'
-import {
-  L2Network as ChildChain,
-  L1Network as ParentChain,
-  getParentForNetwork,
-} from '../dataEntities/networks'
+import { ArbitrumNetwork } from '../dataEntities/networks'
 import { SignerProviderUtils } from '../dataEntities/signerOrProvider'
 import { FetchedEvent, EventFetcher } from '../utils/eventFetcher'
 import { MultiCaller, CallInput } from '../utils/multicall'
@@ -66,19 +62,14 @@ export class InboxTools {
    * Parent chain provider
    */
   private readonly parentChainProvider: Provider
-  /**
-   * Parent chain for the given Arbitrum chain, can be an L1 or an L2
-   */
-  private readonly parentChain: ParentChain | ChildChain
 
   constructor(
     private readonly parentChainSigner: Signer,
-    private readonly childChain: ChildChain
+    private readonly childChain: ArbitrumNetwork
   ) {
     this.parentChainProvider = SignerProviderUtils.getProviderOrThrow(
       this.parentChainSigner
     )
-    this.parentChain = getParentForNetwork(childChain)
   }
 
   /**
@@ -99,10 +90,10 @@ export class InboxTools {
 
     // we take a long average block time of 14s
     // and always move at least 10 blocks
-    const diffBlocks = Math.max(
-      Math.ceil(diff / this.parentChain.blockTime),
-      10
-    )
+
+    // todo(spsjvc): do something about this
+    const blockTime = 12
+    const diffBlocks = Math.max(Math.ceil(diff / blockTime), 10)
 
     return await this.findFirstBlockBelow(
       blockNumber - diffBlocks,
diff --git a/src/lib/message/ChildToParentMessage.ts b/src/lib/message/ChildToParentMessage.ts
index 59c9ae5c4a..aefe70f1e4 100644
--- a/src/lib/message/ChildToParentMessage.ts
+++ b/src/lib/message/ChildToParentMessage.ts
@@ -35,7 +35,10 @@ import {
 import { isDefined } from '../utils/lib'
 import { EventArgs } from '../dataEntities/event'
 import { ChildToParentMessageStatus } from '../dataEntities/message'
-import { getChildChain, getNitroGenesisBlock } from '../dataEntities/networks'
+import {
+  getArbitrumNetwork,
+  getNitroGenesisBlock,
+} from '../dataEntities/networks'
 import { ArbSdkError } from '../dataEntities/errors'
 
 export type ChildToParentTransactionEvent =
@@ -111,7 +114,7 @@ export class ChildToParentMessage {
     hash?: BigNumber,
     indexInBatch?: BigNumber
   ): Promise<(ChildToParentTransactionEvent & { transactionHash: string })[]> {
-    const childChain = await getChildChain(childChainProvider)
+    const childChain = await getArbitrumNetwork(childChainProvider)
     const childChainNitroGenesisBlock = getNitroGenesisBlock(childChain)
 
     const inClassicRange = (blockTag: BlockTag, nitroGenBlock: number) => {
diff --git a/src/lib/message/ChildToParentMessageClassic.ts b/src/lib/message/ChildToParentMessageClassic.ts
index d023afeef4..e646083a7d 100644
--- a/src/lib/message/ChildToParentMessageClassic.ts
+++ b/src/lib/message/ChildToParentMessageClassic.ts
@@ -40,7 +40,7 @@ import { isDefined, wait } from '../utils/lib'
 import { ArbSdkError } from '../dataEntities/errors'
 import { EventArgs } from '../dataEntities/event'
 import { ChildToParentMessageStatus } from '../dataEntities/message'
-import { getChildChain } from '../dataEntities/networks'
+import { getArbitrumNetwork } from '../dataEntities/networks'
 
 export interface MessageBatchProofInfo {
   /**
@@ -213,7 +213,7 @@ export class ChildToParentMessageReaderClassic extends ChildToParentMessageClass
     batchNumber: number
   ) {
     if (!isDefined(this.outboxAddress)) {
-      const childChain = await getChildChain(childProvider)
+      const childChain = await getArbitrumNetwork(childProvider)
 
       // find the outbox where the activation batch number of the next outbox
       // is greater than the supplied batch
diff --git a/src/lib/message/ChildToParentMessageNitro.ts b/src/lib/message/ChildToParentMessageNitro.ts
index 8c9cb6f102..7bdc98f2ad 100644
--- a/src/lib/message/ChildToParentMessageNitro.ts
+++ b/src/lib/message/ChildToParentMessageNitro.ts
@@ -40,7 +40,7 @@ import {
   SignerOrProvider,
 } from '../dataEntities/signerOrProvider'
 import { getBlockRangesForL1Block, isArbitrumChain, wait } from '../utils/lib'
-import { getChildChain } from '../dataEntities/networks'
+import { getArbitrumNetwork } from '../dataEntities/networks'
 import { NodeCreatedEvent, RollupUserLogic } from '../abi/RollupUserLogic'
 import { ArbitrumProvider } from '../utils/arbProvider'
 import { ArbBlock } from '../dataEntities/rpc'
@@ -222,7 +222,7 @@ export class ChildToParentChainMessageReaderNitro extends ChildToParentChainMess
    * Check if this message has already been executed in the Outbox
    */
   protected async hasExecuted(childProvider: Provider): Promise<boolean> {
-    const childChain = await getChildChain(childProvider)
+    const childChain = await getArbitrumNetwork(childProvider)
     const outbox = Outbox__factory.connect(
       childChain.ethBridge.outbox,
       this.parentProvider
@@ -375,7 +375,7 @@ export class ChildToParentChainMessageReaderNitro extends ChildToParentChainMess
 
   protected async getSendProps(childProvider: Provider) {
     if (!this.sendRootConfirmed) {
-      const childChain = await getChildChain(childProvider)
+      const childChain = await getArbitrumNetwork(childProvider)
 
       const rollup = RollupUserLogic__factory.connect(
         childChain.ethBridge.rollup,
@@ -457,7 +457,7 @@ export class ChildToParentChainMessageReaderNitro extends ChildToParentChainMess
   public async getFirstExecutableBlock(
     childProvider: Provider
   ): Promise<BigNumber | null> {
-    const childChain = await getChildChain(childProvider)
+    const childChain = await getArbitrumNetwork(childProvider)
 
     const rollup = RollupUserLogic__factory.connect(
       childChain.ethBridge.rollup,
@@ -574,7 +574,7 @@ export class ChildToParentChainMessageWriterNitro extends ChildToParentChainMess
       )
     }
     const proof = await this.getOutboxProof(childProvider)
-    const childChain = await getChildChain(childProvider)
+    const childChain = await getArbitrumNetwork(childProvider)
     const outbox = Outbox__factory.connect(
       childChain.ethBridge.outbox,
       this.parentSigner
diff --git a/src/lib/message/ParentToChildMessage.ts b/src/lib/message/ParentToChildMessage.ts
index a24280385d..dace3146a5 100644
--- a/src/lib/message/ParentToChildMessage.ts
+++ b/src/lib/message/ParentToChildMessage.ts
@@ -44,7 +44,7 @@ import {
 import { ArbSdkError } from '../dataEntities/errors'
 import { Overrides } from 'ethers'
 import { ChildTransactionReceipt, RedeemTransaction } from './ChildTransaction'
-import { getChildChain } from '../../lib/dataEntities/networks'
+import { getArbitrumNetwork } from '../../lib/dataEntities/networks'
 import { RetryableMessageParams } from '../dataEntities/message'
 import { getTransactionReceipt, isDefined } from '../utils/lib'
 import { EventFetcher } from '../utils/eventFetcher'
@@ -323,7 +323,7 @@ export class ParentToChildMessageReader extends ParentToChildMessage {
    * @returns TransactionReceipt of the first successful redeem if exists, otherwise the current status of the message.
    */
   public async getSuccessfulRedeem(): Promise<ParentToChildMessageWaitResult> {
-    const chainNetwork = await getChildChain(this.chainProvider)
+    const chainNetwork = await getArbitrumNetwork(this.chainProvider)
     const eventFetcher = new EventFetcher(this.chainProvider)
     const creationReceipt = await this.getRetryableCreationReceipt()
 
diff --git a/src/lib/message/ParentToChildMessageCreator.ts b/src/lib/message/ParentToChildMessageCreator.ts
index e06a0105ce..5e83c164ef 100644
--- a/src/lib/message/ParentToChildMessageCreator.ts
+++ b/src/lib/message/ParentToChildMessageCreator.ts
@@ -11,7 +11,7 @@ import {
   ParentTransactionReceipt,
 } from './ParentTransaction'
 import { Inbox__factory } from '../abi/factories/Inbox__factory'
-import { getChildChain } from '../dataEntities/networks'
+import { getArbitrumNetwork } from '../dataEntities/networks'
 import { ERC20Inbox__factory } from '../abi/factories/ERC20Inbox__factory'
 import { PayableOverrides } from '@ethersproject/contracts'
 import { SignerProviderUtils } from '../dataEntities/signerOrProvider'
@@ -155,7 +155,7 @@ export class ParentToChildMessageCreator {
       options
     )
 
-    const childChain = await getChildChain(childProvider)
+    const childChain = await getArbitrumNetwork(childProvider)
     const nativeTokenIsEth = typeof childChain.nativeToken === 'undefined'
 
     const data = ParentToChildMessageCreator.getTicketCreationRequestCallData(
diff --git a/src/lib/message/ParentToChildMessageGasEstimator.ts b/src/lib/message/ParentToChildMessageGasEstimator.ts
index a4b5098d34..f8ae584ecf 100644
--- a/src/lib/message/ParentToChildMessageGasEstimator.ts
+++ b/src/lib/message/ParentToChildMessageGasEstimator.ts
@@ -1,11 +1,12 @@
 import { Provider } from '@ethersproject/abstract-provider'
 import { BigNumber, BigNumberish } from '@ethersproject/bignumber'
-import { BytesLike, constants, utils } from 'ethers'
+import { BytesLike, constants } from 'ethers'
+import { parseEther, dataLength } from 'ethers-v6'
 import { Inbox__factory } from '../abi/factories/Inbox__factory'
 import { NodeInterface__factory } from '../abi/factories/NodeInterface__factory'
 import { NODE_INTERFACE_ADDRESS } from '../dataEntities/constants'
 import { ArbSdkError } from '../dataEntities/errors'
-import { getChildChain } from '../dataEntities/networks'
+import { getArbitrumNetwork } from '../dataEntities/networks'
 import {
   RetryableData,
   RetryableDataTools,
@@ -125,7 +126,7 @@ export class ParentToChildMessageGasEstimator {
   ): Promise<ParentToChildMessageGasParams['maxSubmissionCost']> {
     const defaultedOptions = this.applySubmissionPriceDefaults(options)
 
-    const network = await getChildChain(this.childProvider)
+    const network = await getArbitrumNetwork(this.childProvider)
     const inbox = Inbox__factory.connect(
       network.ethBridge.inbox,
       parentProvider
@@ -157,7 +158,7 @@ export class ParentToChildMessageGasEstimator {
       callValueRefundAddress,
       data,
     }: ParentToChildMessageNoGasParams,
-    senderDeposit: BigNumber = utils.parseEther('1').add(l2CallValue)
+    senderDeposit: BigNumber = BigNumber.from(parseEther('1')).add(l2CallValue)
   ): Promise<ParentToChildMessageGasParams['gasLimit']> {
     const nodeInterface = NodeInterface__factory.connect(
       NODE_INTERFACE_ADDRESS,
@@ -233,7 +234,7 @@ export class ParentToChildMessageGasEstimator {
     const maxSubmissionFeePromise = this.estimateSubmissionFee(
       parentProvider,
       parentBaseFee,
-      utils.hexDataLength(data),
+      dataLength(data),
       options?.maxSubmissionFee
     )
 
diff --git a/src/lib/message/ParentTransaction.ts b/src/lib/message/ParentTransaction.ts
index 7c82c1ff12..2d1a864aff 100644
--- a/src/lib/message/ParentTransaction.ts
+++ b/src/lib/message/ParentTransaction.ts
@@ -112,7 +112,7 @@ export class ParentTransactionReceipt implements TransactionReceipt {
     const network = await getArbitrumNetwork(provider)
 
     // all networks except Arbitrum One started off with Nitro
-    if (network.chainID === 42161) {
+    if (network.chainId === 42161) {
       return this.blockNumber < ARB1_NITRO_GENESIS_L1_BLOCK
     }
 
@@ -217,7 +217,7 @@ export class ParentTransactionReceipt implements TransactionReceipt {
     childProvider: Provider
   ): Promise<ParentToChildMessageReaderClassic[]> {
     const network = await getArbitrumNetwork(childProvider)
-    const chainID = network.chainID.toString()
+    const chainId = network.chainId.toString()
     const isClassic = await this.isClassic(childProvider)
 
     // throw on nitro events
@@ -235,7 +235,7 @@ export class ParentTransactionReceipt implements TransactionReceipt {
       messageNum =>
         new ParentToChildMessageReaderClassic(
           childProvider,
-          BigNumber.from(chainID).toNumber(),
+          BigNumber.from(chainId).toNumber(),
           messageNum
         )
     )
@@ -255,7 +255,7 @@ export class ParentTransactionReceipt implements TransactionReceipt {
       childSignerOrProvider
     )
     const network = await getArbitrumNetwork(provider)
-    const chainID = network.chainID.toString()
+    const chainId = network.chainId.toString()
     const isClassic = await this.isClassic(provider)
 
     // throw on classic events
@@ -282,7 +282,7 @@ export class ParentTransactionReceipt implements TransactionReceipt {
 
         return ParentToChildMessage.fromEventComponents(
           childSignerOrProvider,
-          BigNumber.from(chainID).toNumber(),
+          BigNumber.from(chainId).toNumber(),
           mn.bridgeMessageEvent.sender,
           mn.inboxMessageEvent.messageNum,
           mn.bridgeMessageEvent.baseFeeL1,
diff --git a/src/lib/utils/multicall.ts b/src/lib/utils/multicall.ts
index 9d5d20c907..1e93f623ea 100644
--- a/src/lib/utils/multicall.ts
+++ b/src/lib/utils/multicall.ts
@@ -17,19 +17,13 @@
 'use strict'
 
 import { Provider } from '@ethersproject/abstract-provider'
-import { BigNumber, utils } from 'ethers'
+import { BigNumber } from 'ethers'
+import { isHexString, decodeBytes32String, dataLength } from 'ethers-v6'
 
 import { ERC20__factory } from '../abi/factories/ERC20__factory'
 import { Multicall2 } from '../abi/Multicall2'
 import { Multicall2__factory } from '../abi/factories/Multicall2__factory'
-import { ArbSdkError } from '../dataEntities/errors'
-import {
-  isL1Network,
-  L1Network,
-  l1Networks,
-  L2Network,
-  l2Networks,
-} from '../dataEntities/networks'
+import { getMulticallAddress } from '../dataEntities/networks'
 
 /**
  * Input to multicall aggregator
@@ -130,33 +124,7 @@ export class MultiCaller {
    * @returns
    */
   public static async fromProvider(provider: Provider): Promise<MultiCaller> {
-    const chainId = (await provider.getNetwork()).chainId
-    const l2Network = l2Networks[chainId] as L2Network | undefined
-    const l1Network = l1Networks[chainId] as L1Network | undefined
-
-    const network = l2Network || l1Network
-    if (!network) {
-      throw new ArbSdkError(
-        `Unexpected network id: ${chainId}. Ensure that chain ${chainId} has been added as a network.`
-      )
-    }
-
-    let multiCallAddr: string
-    if (isL1Network(network)) {
-      // If the network is an L1, find one of its L2s and pick up the multicall address from there
-      const firstL2 = [...Object.values(l2Networks)].find(
-        chain => chain.parentChainId === network.chainID
-      )
-      if (!firstL2)
-        throw new ArbSdkError(
-          `No children chains found for network: ${network.chainID}`
-        )
-      multiCallAddr = firstL2.tokenBridge.l1MultiCall
-    } else {
-      multiCallAddr = network.tokenBridge.l2Multicall
-    }
-
-    return new MultiCaller(provider, multiCallAddr)
+    return new MultiCaller(provider, await getMulticallAddress(provider))
   }
 
   /**
@@ -284,7 +252,7 @@ export class MultiCaller {
     const erc20Iface = ERC20__factory.createInterface()
 
     const isBytes32 = (data: string) =>
-      utils.isHexString(data) && utils.hexDataLength(data) === 32
+      isHexString(data) && dataLength(data) === 32
 
     const input = []
     for (const t of erc20Addresses) {
@@ -339,7 +307,7 @@ export class MultiCaller {
             // Maker doesn't follow the erc20 spec and returns bytes32 data.
             // https://etherscan.io/token/0x9f8F72aA9304c8B593d555F12eF6589cC3A579A2#readContract
             if (isBytes32(returnData)) {
-              return utils.parseBytes32String(returnData) as string
+              return decodeBytes32String(returnData) as string
             } else
               return erc20Iface.decodeFunctionResult(
                 'name',
@@ -357,7 +325,7 @@ export class MultiCaller {
             // Maker doesn't follow the erc20 spec and returns bytes32 data.
             // https://etherscan.io/token/0x9f8F72aA9304c8B593d555F12eF6589cC3A579A2#readContract
             if (isBytes32(returnData)) {
-              return utils.parseBytes32String(returnData) as string
+              return decodeBytes32String(returnData) as string
             } else
               return erc20Iface.decodeFunctionResult(
                 'symbol',
diff --git a/src/lib/utils/types.ts b/src/lib/utils/types.ts
index dc0707ea5b..48d60a6a2e 100644
--- a/src/lib/utils/types.ts
+++ b/src/lib/utils/types.ts
@@ -14,3 +14,9 @@ export type PartialPick<T, K extends keyof T> = OmitTyped<T, K> & Partial<T>
  * Make the specified properties required
  */
 export type RequiredPick<T, K extends keyof T> = Required<Pick<T, K>> & T
+
+// https://twitter.com/mattpocockuk/status/1622730173446557697
+export type Prettify<T> = {
+  [K in keyof T]: T[K]
+  // eslint-disable-next-line @typescript-eslint/ban-types
+} & {}
diff --git a/tests/fork/inbox.test.ts b/tests/fork/inbox.test.ts
index 7362c01143..85e58893e2 100644
--- a/tests/fork/inbox.test.ts
+++ b/tests/fork/inbox.test.ts
@@ -29,13 +29,12 @@ import { SequencerInbox__factory } from '../../src/lib/abi/factories/SequencerIn
 import { InboxTools } from '../../src'
 
 import { ethers, network } from 'hardhat'
-import { zeroPadValue } from 'ethers-v6'
+import { ContractTransaction, Signer } from 'ethers'
+import { zeroPadValue, solidityPackedKeccak256 } from 'ethers-v6'
 import {
-  ChildChain as L2Network,
-  getChildChain as getL2Network,
+  ArbitrumNetwork,
+  getArbitrumNetwork,
 } from '../../src/lib/dataEntities/networks'
-import { solidityKeccak256 } from 'ethers/lib/utils'
-import { ContractTransaction, Signer } from 'ethers'
 
 const submitL2Tx = async (
   tx: {
@@ -46,7 +45,7 @@ const submitL2Tx = async (
     maxFeePerGas: BigNumber
     gasLimit: BigNumber
   },
-  l2Network: L2Network,
+  l2Network: ArbitrumNetwork,
   l1Signer: Signer
 ): Promise<ContractTransaction> => {
   const inbox = Inbox__factory.connect(l2Network.ethBridge.inbox, l1Signer)
@@ -67,7 +66,7 @@ describe('Inbox tools', () => {
     const signer = signers[0]
     const provider = signer.provider!
 
-    const arbitrumOne = await getL2Network(42161)
+    const arbitrumOne = await getArbitrumNetwork(42161)
 
     const sequencerInbox = SequencerInbox__factory.connect(
       arbitrumOne.ethBridge.sequencerInbox,
@@ -210,7 +209,7 @@ describe('Inbox tools', () => {
       maxFeePerGas: BigNumber.from(21000000000),
       nonce: 1,
     }
-    const messageDataHash = solidityKeccak256(
+    const messageDataHash = solidityPackedKeccak256(
       ['uint8', 'uint256', 'uint256', 'uint256', 'uint256', 'uint256', 'bytes'],
       [
         0,
diff --git a/tests/integration/childTransactionReceipt.test.ts b/tests/integration/childTransactionReceipt.test.ts
index b5fc17372e..2f1490d8b5 100644
--- a/tests/integration/childTransactionReceipt.test.ts
+++ b/tests/integration/childTransactionReceipt.test.ts
@@ -28,7 +28,7 @@ import {
 import { ChildTransactionReceipt } from '../../src'
 import { JsonRpcProvider } from '@ethersproject/providers'
 import { BigNumber, Wallet } from 'ethers'
-import { parseEther } from 'ethers/lib/utils'
+import { parseEther } from 'ethers-v6'
 import { testSetup } from '../../scripts/testSetup'
 
 describe('ArbProvider', () => {
@@ -43,8 +43,8 @@ describe('ArbProvider', () => {
     // set up miners
     const miner1 = Wallet.createRandom().connect(parentSigner.provider!)
     const miner2 = Wallet.createRandom().connect(childSigner.provider!)
-    await fundParentSigner(miner1, parseEther('0.1'))
-    await fundChildSigner(miner2, parseEther('0.1'))
+    await fundParentSigner(miner1, BigNumber.from(parseEther('0.1')))
+    await fundChildSigner(miner2, BigNumber.from(parseEther('0.1')))
     const state = { mining: true }
     mineUntilStop(miner1, state)
     mineUntilStop(miner2, state)
diff --git a/tests/integration/custom-fee-token/customFeeTokenTestHelpers.ts b/tests/integration/custom-fee-token/customFeeTokenTestHelpers.ts
index ae8e816120..2995fd3ea5 100644
--- a/tests/integration/custom-fee-token/customFeeTokenTestHelpers.ts
+++ b/tests/integration/custom-fee-token/customFeeTokenTestHelpers.ts
@@ -1,6 +1,6 @@
 import { StaticJsonRpcProvider } from '@ethersproject/providers'
-import { Signer, Wallet, utils } from 'ethers'
-import { ZeroAddress } from 'ethers-v6'
+import { Signer, Wallet } from 'ethers'
+import { ZeroAddress, parseEther, sha256, toUtf8Bytes } from 'ethers-v6'
 
 import {
   testSetup as _testSetup,
@@ -49,13 +49,13 @@ export async function fundParentCustomFeeToken(
   }
 
   const deployerWallet = new Wallet(
-    utils.sha256(utils.toUtf8Bytes('user_token_bridge_deployer')),
+    sha256(toUtf8Bytes('user_token_bridge_deployer')),
     ethProvider()
   )
 
   const tokenContract = ERC20__factory.connect(nativeToken, deployerWallet)
 
-  const tx = await tokenContract.transfer(address, utils.parseEther('10'))
+  const tx = await tokenContract.transfer(address, parseEther('10'))
   await tx.wait()
 }
 
@@ -96,7 +96,7 @@ export async function fundChildCustomFeeToken(childSigner: Signer) {
 
   const tx = await deployerWallet.sendTransaction({
     to: await childSigner.getAddress(),
-    value: utils.parseEther('1'),
+    value: parseEther('1'),
   })
   await tx.wait()
 }
diff --git a/tests/integration/customerc20.test.ts b/tests/integration/customerc20.test.ts
index a7a0fd0625..5e14d1e79b 100644
--- a/tests/integration/customerc20.test.ts
+++ b/tests/integration/customerc20.test.ts
@@ -17,7 +17,7 @@
 'use strict'
 
 import { expect } from 'chai'
-import { Signer, Wallet, utils } from 'ethers'
+import { Signer, Wallet } from 'ethers'
 import { ZeroAddress, parseEther } from 'ethers-v6'
 import { BigNumber } from '@ethersproject/bignumber'
 import { Logger, LogLevel } from '@ethersproject/logger'
@@ -123,7 +123,7 @@ describe('Custom ERC20', () => {
   it('deposits erc20 with extra ETH', async () => {
     await depositToken({
       depositAmount,
-      ethDepositAmount: utils.parseEther('0.0005'),
+      ethDepositAmount: BigNumber.from(parseEther('0.0005')),
       parentTokenAddress: testState.l1CustomToken.address,
       erc20Bridger: testState.adminErc20Bridger,
       parentSigner: testState.parentSigner,
@@ -137,7 +137,7 @@ describe('Custom ERC20', () => {
     const randomAddress = Wallet.createRandom().address
     await depositToken({
       depositAmount,
-      ethDepositAmount: utils.parseEther('0.0005'),
+      ethDepositAmount: BigNumber.from(parseEther('0.0005')),
       parentTokenAddress: testState.l1CustomToken.address,
       erc20Bridger: testState.adminErc20Bridger,
       parentSigner: testState.parentSigner,
diff --git a/tests/integration/ethBridgeAddresses.test.ts b/tests/integration/ethBridgeAddresses.test.ts
index 57c9eb8b62..6fa8fc0671 100644
--- a/tests/integration/ethBridgeAddresses.test.ts
+++ b/tests/integration/ethBridgeAddresses.test.ts
@@ -3,7 +3,7 @@ import { expect } from 'chai'
 import {
   EthBridge,
   getEthBridgeInformation,
-  getChildChain as getL2Network,
+  getArbitrumNetwork,
 } from '../../src/lib/dataEntities/networks'
 import dotenv from 'dotenv'
 dotenv.config()
@@ -14,7 +14,7 @@ dotenv.config()
  */
 describe('Obtain deployed bridge addresses', () => {
   it('obtains deployed ETH Bridge addresses', async () => {
-    const arbOneL2Network = await getL2Network(42161)
+    const arbOneL2Network = await getArbitrumNetwork(42161)
     const ethProvider = new JsonRpcProvider(
       process.env['MAINNET_RPC'] as string
     )
diff --git a/tests/integration/parentToChildMessageCreator.test.ts b/tests/integration/parentToChildMessageCreator.test.ts
index 079ea7ea3c..30f3da9898 100644
--- a/tests/integration/parentToChildMessageCreator.test.ts
+++ b/tests/integration/parentToChildMessageCreator.test.ts
@@ -17,7 +17,8 @@
 'use strict'
 
 import { expect } from 'chai'
-import { providers, utils } from 'ethers'
+import { BigNumber, providers } from 'ethers'
+import { parseEther } from 'ethers-v6'
 import { fundParentSigner, skipIfMainnet } from './testHelpers'
 import { testSetup } from '../../scripts/testSetup'
 import { ParentToChildMessageCreator } from '../../src/lib/message/ParentToChildMessageCreator'
@@ -35,7 +36,7 @@ describe('ParentToChildMessageCreator', () => {
   })
 
   // Testing amount
-  const testAmount = utils.parseEther('0.01')
+  const testAmount = BigNumber.from(parseEther('0.01'))
 
   it('allows the creation of Retryable Tickets sending parameters', async () => {
     const { parentSigner, childSigner } = await testSetup()
diff --git a/tests/integration/retryableData.test.ts b/tests/integration/retryableData.test.ts
index a81768dccf..9db5c920c9 100644
--- a/tests/integration/retryableData.test.ts
+++ b/tests/integration/retryableData.test.ts
@@ -18,13 +18,12 @@
 
 import { assert, expect } from 'chai'
 import { BigNumber } from '@ethersproject/bignumber'
-import { hexlify } from 'ethers-v6'
+import { hexlify, parseEther, randomBytes } from 'ethers-v6'
 import { TestERC20__factory } from '../../src/lib/abi/factories/TestERC20__factory'
 import { fundParentSigner, skipIfMainnet } from './testHelpers'
 import { RetryableDataTools } from '../../src'
 import { Wallet } from 'ethers'
 import { testSetup } from '../../scripts/testSetup'
-import { parseEther, randomBytes } from 'ethers/lib/utils'
 import { Inbox__factory } from '../../src/lib/abi/factories/Inbox__factory'
 import { GasOverrides } from '../../src/lib/message/ParentToChildMessageGasEstimator'
 const depositAmount = BigNumber.from(100)
@@ -146,7 +145,7 @@ describe('RevertData', () => {
 
   it('is the same as what we estimate in erc20Bridger', async () => {
     const { erc20Bridger, parentSigner, childSigner } = await testSetup()
-    await fundParentSigner(parentSigner, parseEther('2'))
+    await fundParentSigner(parentSigner, BigNumber.from(parseEther('2')))
 
     const deployErc20 = new TestERC20__factory().connect(parentSigner)
     const testToken = await deployErc20.deploy()
diff --git a/tests/integration/sanity.test.ts b/tests/integration/sanity.test.ts
index 81e6b9e138..95e081b6f5 100644
--- a/tests/integration/sanity.test.ts
+++ b/tests/integration/sanity.test.ts
@@ -28,7 +28,7 @@ import { L2ERC20Gateway__factory } from '../../src/lib/abi/factories/L2ERC20Gate
 import { L1ERC20Gateway__factory } from '../../src/lib/abi/factories/L1ERC20Gateway__factory'
 
 import { testSetup } from '../../scripts/testSetup'
-import { randomBytes, hexlify } from 'ethers/lib/utils'
+import { randomBytes, hexlify } from 'ethers-v6'
 import { itOnlyWhenEth } from './custom-fee-token/mochaExtensions'
 
 const expectIgnoreCase = (expected: string, actual: string) => {
diff --git a/tests/integration/standarderc20.test.ts b/tests/integration/standarderc20.test.ts
index af08fc29ca..489d744e93 100644
--- a/tests/integration/standarderc20.test.ts
+++ b/tests/integration/standarderc20.test.ts
@@ -17,7 +17,7 @@
 'use strict'
 
 import { expect } from 'chai'
-import { Signer, Wallet, utils, constants } from 'ethers'
+import { Signer, Wallet, constants } from 'ethers'
 import { BigNumber } from '@ethersproject/bignumber'
 import { TestERC20__factory } from '../../src/lib/abi/factories/TestERC20__factory'
 import {
@@ -51,6 +51,7 @@ import {
   isArbitrumNetworkWithCustomFeeToken,
 } from './custom-fee-token/customFeeTokenTestHelpers'
 import { itOnlyWhenCustomGasToken } from './custom-fee-token/mochaExtensions'
+import { parseEther } from 'ethers-v6'
 
 const depositAmount = BigNumber.from(100)
 const withdrawalAmount = BigNumber.from(10)
@@ -302,7 +303,7 @@ describe('standard ERC20', () => {
   it('deposits erc20 with extra ETH', async () => {
     await depositToken({
       depositAmount,
-      ethDepositAmount: utils.parseEther('0.0005'),
+      ethDepositAmount: BigNumber.from(parseEther('0.0005')),
       parentTokenAddress: testState.parentToken.address,
       erc20Bridger: testState.erc20Bridger,
       parentSigner: testState.parentSigner,
@@ -316,7 +317,7 @@ describe('standard ERC20', () => {
     const randomAddress = Wallet.createRandom().address
     await depositToken({
       depositAmount,
-      ethDepositAmount: utils.parseEther('0.0005'),
+      ethDepositAmount: BigNumber.from(parseEther('0.0005')),
       parentTokenAddress: testState.parentToken.address,
       erc20Bridger: testState.erc20Bridger,
       parentSigner: testState.parentSigner,
diff --git a/tests/integration/testHelpers.ts b/tests/integration/testHelpers.ts
index a2a1c6b5b6..7ad2ece9a9 100644
--- a/tests/integration/testHelpers.ts
+++ b/tests/integration/testHelpers.ts
@@ -443,10 +443,10 @@ export const skipIfMainnet = (() => {
   let chainId: number
   return async (testContext: Mocha.Context) => {
     if (!chainId) {
-      const { parentChain } = await testSetup()
-      chainId = parentChain.chainID
+      const { childChain } = await testSetup()
+      chainId = childChain.chainId
     }
-    if (chainId === 1) {
+    if (chainId === 42161 || chainId === 42170) {
       console.error("You're writing to the chain on mainnet lol stop")
       testContext.skip()
     }
diff --git a/tests/unit/childToParentMessageEvents.test.ts b/tests/unit/childToParentMessageEvents.test.ts
index 0d505da4c9..0e5d3f7316 100644
--- a/tests/unit/childToParentMessageEvents.test.ts
+++ b/tests/unit/childToParentMessageEvents.test.ts
@@ -43,7 +43,7 @@ describe('ChildToParentMessage events', () => {
     const latestBlock = getNitroGenesisBlock(l2Network) + 1000
     when(l2ProviderMock.getBlockNumber()).thenResolve(latestBlock)
     when(l2ProviderMock.getNetwork()).thenResolve({
-      chainId: l2Network.chainID,
+      chainId: l2Network.chainId,
     } as any)
     when(l2ProviderMock._isProvider).thenReturn(true)
     when(l2ProviderMock.getLogs(anything())).thenResolve([])
diff --git a/tests/unit/messageDataParser.test.ts b/tests/unit/messageDataParser.test.ts
index e6b359f59c..e7ba0a9658 100644
--- a/tests/unit/messageDataParser.test.ts
+++ b/tests/unit/messageDataParser.test.ts
@@ -4,7 +4,7 @@
 import { expect } from 'chai'
 
 import { BigNumber } from 'ethers'
-import { parseEther } from 'ethers/lib/utils'
+import { parseEther } from 'ethers-v6'
 import { SubmitRetryableMessageDataParser } from '../../src/lib/message/messageDataParser'
 
 describe('SubmitRetryableMessageDataParser', () => {
diff --git a/tests/unit/multicall.test.ts b/tests/unit/multicall.test.ts
index cef88f399c..04e30a3b3b 100644
--- a/tests/unit/multicall.test.ts
+++ b/tests/unit/multicall.test.ts
@@ -1,7 +1,7 @@
 'use strict'
 
 import {
-  getChildChain as getL2Network,
+  getArbitrumNetwork,
   getNitroGenesisBlock,
 } from '../../src/lib/dataEntities/networks'
 import { providers } from 'ethers'
@@ -12,18 +12,18 @@ import { MultiCaller } from '../../src'
 
 describe('Multicall', () => {
   const createProviderMock = async (networkChoiceOverride?: number) => {
-    const l2Network = await getL2Network(networkChoiceOverride || 42161)
+    const l2Network = await getArbitrumNetwork(networkChoiceOverride || 42161)
 
     const l2ProviderMock = mock(providers.JsonRpcProvider)
     const latestBlock = getNitroGenesisBlock(l2Network) + 1000
     when(l2ProviderMock.getBlockNumber()).thenResolve(latestBlock)
     when(l2ProviderMock.getNetwork()).thenResolve({
-      chainId: l2Network.chainID,
+      chainId: l2Network.chainId,
     } as any)
     when(l2ProviderMock._isProvider).thenReturn(true)
     when(l2ProviderMock.getLogs(anything())).thenResolve([])
 
-    /* 
+    /*
     This test data is taken from an actual example of a mainnet multicall. To produce this data we do the following:
     1. Pass mainnet args to the multicall class, instantiated with a mock provider
     2. Capture the .call request that was made on the provider
diff --git a/tests/unit/network.test.ts b/tests/unit/network.test.ts
index dac3faf2e4..75d41559d4 100644
--- a/tests/unit/network.test.ts
+++ b/tests/unit/network.test.ts
@@ -1,19 +1,17 @@
 import { expect } from 'chai'
 import {
   resetNetworksToDefault,
-  addCustomNetwork,
-  getL1Network,
+  addCustomArbitrumNetwork,
   getArbitrumNetwork,
-  l1Networks,
   l2Networks as arbitrumNetworks,
   getChildrenForNetwork,
-  isParentChain,
+  isParentNetwork,
+  getMulticallAddress,
 } from '../../src/lib/dataEntities/networks'
 
 const ethereumMainnetChainId = 1
 const arbitrumOneChainId = 42161
 
-const mockL1ChainId = 111111
 const mockL2ChainId = 222222
 const mockL3ChainId = 99999999
 
@@ -23,71 +21,40 @@ describe('Networks', async () => {
   })
 
   describe('adding networks', () => {
-    it('adds a custom Arbitrum network', async function () {
+    it('adds a custom L2 network', async function () {
       const arbitrumOne = await getArbitrumNetwork(arbitrumOneChainId)
 
       const customArbitrumNetwork = {
         ...arbitrumOne,
-        chainID: mockL2ChainId,
+        chainId: mockL2ChainId,
         parentChainId: ethereumMainnetChainId,
         isArbitrum: true,
         isCustom: true,
       } as const
 
-      addCustomNetwork({ customArbitrumNetwork })
+      addCustomArbitrumNetwork(customArbitrumNetwork)
 
       expect(await getArbitrumNetwork(mockL2ChainId)).to.be.ok
 
       // assert network has correct parent
       const arbitrumNetwork = await getArbitrumNetwork(
-        customArbitrumNetwork.chainID
+        customArbitrumNetwork.chainId
       )
       expect(arbitrumNetwork.parentChainId).to.equal(ethereumMainnetChainId)
     })
 
-    it('adds a custom L1 and Arbitrum network', async function () {
-      const ethereumMainnet = await getL1Network(ethereumMainnetChainId)
-      const arbitrumOne = await getArbitrumNetwork(arbitrumOneChainId)
-
-      const customL1Network = {
-        ...ethereumMainnet,
-        chainID: mockL1ChainId,
-        isArbitrum: false,
-        isCustom: true,
-      } as const
-
-      const customArbitrumNetwork = {
-        ...arbitrumOne,
-        parentChainId: mockL1ChainId,
-        chainID: mockL2ChainId,
-        isArbitrum: true,
-        isCustom: true,
-      } as const
-
-      addCustomNetwork({ customL1Network, customArbitrumNetwork })
-
-      expect(await getL1Network(mockL1ChainId)).to.be.ok
-      expect(await getArbitrumNetwork(mockL2ChainId)).to.be.ok
-
-      // assert network has correct parent
-      const arbitrumNetwork = await getArbitrumNetwork(
-        customArbitrumNetwork.chainID
-      )
-      expect(arbitrumNetwork.parentChainId).to.equal(mockL1ChainId)
-    })
-
     it('adds a custom L3 network', async function () {
       const arbitrumOne = await getArbitrumNetwork(arbitrumOneChainId)
 
       const customArbitrumNetwork = {
         ...arbitrumOne,
-        chainID: mockL3ChainId,
+        chainId: mockL3ChainId,
         parentChainId: arbitrumOneChainId,
         isArbitrum: true,
         isCustom: true,
       } as const
 
-      addCustomNetwork({ customArbitrumNetwork })
+      addCustomArbitrumNetwork(customArbitrumNetwork)
 
       expect(await getArbitrumNetwork(mockL3ChainId)).to.be.ok
 
@@ -95,128 +62,12 @@ describe('Networks', async () => {
       const l3Network = await getArbitrumNetwork(mockL3ChainId)
       expect(l3Network.parentChainId).to.equal(arbitrumOneChainId)
     })
-
-    it('adds a custom L1, L2, and L3 network', async function () {
-      const ethereumMainnet = await getL1Network(ethereumMainnetChainId)
-      const arbitrumOne = await getArbitrumNetwork(arbitrumOneChainId)
-
-      const customL1Network = {
-        ...ethereumMainnet,
-        chainID: mockL1ChainId,
-        isArbitrum: false,
-        isCustom: true,
-      } as const
-
-      const customArbitrumNetwork = {
-        ...arbitrumOne,
-        chainID: mockL2ChainId,
-        parentChainId: mockL1ChainId,
-        isArbitrum: true,
-        isCustom: true,
-      } as const
-
-      addCustomNetwork({ customL1Network, customArbitrumNetwork })
-
-      expect(await getL1Network(mockL1ChainId)).to.be.ok
-      expect(await getArbitrumNetwork(mockL2ChainId)).to.be.ok
-
-      // assert network has correct parent
-      const arbitrumNetwork = await getArbitrumNetwork(mockL2ChainId)
-      expect(arbitrumNetwork.parentChainId).to.equal(mockL1ChainId)
-
-      const customL3Network = {
-        ...arbitrumOne,
-        chainID: mockL3ChainId,
-        parentChainId: mockL2ChainId,
-        isArbitrum: true,
-        isCustom: true,
-      } as const
-
-      addCustomNetwork({ customArbitrumNetwork: customL3Network })
-
-      expect(await getArbitrumNetwork(mockL3ChainId)).to.be.ok
-
-      // assert network has correct parent
-      const l3Network = await getArbitrumNetwork(mockL3ChainId)
-      expect(l3Network.parentChainId).to.equal(mockL2ChainId)
-    })
-
-    it('fails to add a custom L1 and Arbitrum network if they do not match', async function () {
-      const ethereumMainnet = await getL1Network(ethereumMainnetChainId)
-      const arbitrumOne = await getArbitrumNetwork(arbitrumOneChainId)
-
-      const wrongParentChainId = 1241244
-
-      const customL1Network = {
-        ...ethereumMainnet,
-        chainID: mockL1ChainId,
-        isArbitrum: false,
-        isCustom: true,
-      } as const
-
-      const customArbitrumNetwork = {
-        ...arbitrumOne,
-        parentChainId: wrongParentChainId,
-        chainID: mockL2ChainId,
-        isArbitrum: true,
-        isCustom: true,
-      } as const
-
-      try {
-        addCustomNetwork({ customL1Network, customArbitrumNetwork })
-      } catch (err) {
-        // should fail
-        expect(err).to.be.an('error')
-        expect((err as Error).message).to.be.eq(
-          `Partner chain id for Arbitrum network ${customArbitrumNetwork.chainID} doesn't match the provided L1 network. Expected ${customL1Network.chainID} but got ${wrongParentChainId}.`
-        )
-      }
-    })
-
-    it('fails to add a custom L3 without previously registering L2', async function () {
-      const arbitrumOne = await getArbitrumNetwork(arbitrumOneChainId)
-
-      try {
-        addCustomNetwork({
-          customArbitrumNetwork: {
-            ...arbitrumOne,
-            chainID: mockL3ChainId,
-            parentChainId: mockL2ChainId,
-            isArbitrum: true,
-            isCustom: true,
-          },
-        })
-      } catch (err) {
-        // should fail
-        expect(err).to.be.an('error')
-        expect((err as Error).message).to.be.eq(
-          `Network ${mockL3ChainId}'s parent network ${mockL2ChainId} is not recognized`
-        )
-      }
-    })
   })
 
   describe('fetching networks', () => {
-    it('successfully fetches an L1 network with `getL1Network`', async function () {
-      const network = await getL1Network(ethereumMainnetChainId)
-      expect(network.chainID).to.be.eq(ethereumMainnetChainId)
-    })
-
     it('successfully fetches an Arbitrum network with `getArbitrumNetwork`', async function () {
       const network = await getArbitrumNetwork(arbitrumOneChainId)
-      expect(network.chainID).to.be.eq(arbitrumOneChainId)
-    })
-
-    it('fails to fetch a registered Arbitrum network with `getL1Network`', async function () {
-      try {
-        await getL1Network(arbitrumOneChainId)
-      } catch (err) {
-        // should fail
-        expect(err).to.be.an('error')
-        expect((err as Error).message).to.be.eq(
-          `Unrecognized network ${arbitrumOneChainId}.`
-        )
-      }
+      expect(network.chainId).to.be.eq(arbitrumOneChainId)
     })
 
     it('fails to fetch a registered L1 network with `getArbitrumNetwork`', async function () {
@@ -236,33 +87,20 @@ describe('Networks', async () => {
 
       const customL3Network = {
         ...arbitrumOne,
-        chainID: mockL3ChainId,
+        chainId: mockL3ChainId,
         parentChainId: arbitrumOneChainId,
         isArbitrum: true,
         isCustom: true,
       } as const
 
-      addCustomNetwork({ customArbitrumNetwork: customL3Network })
+      addCustomArbitrumNetwork(customL3Network)
 
       const l3Network = await getArbitrumNetwork(mockL3ChainId)
-      expect(l3Network.chainID).to.be.eq(mockL3ChainId)
+      expect(l3Network.chainId).to.be.eq(mockL3ChainId)
       // assert network has correct parent
       expect(l3Network.parentChainId).to.equal(arbitrumOneChainId)
     })
 
-    it('fails to fetch an unrecognized L1 network', async () => {
-      const chainId = 9999
-
-      try {
-        await getL1Network(chainId)
-      } catch (err) {
-        expect(err).to.be.instanceOf(Error)
-        expect((err as Error).message).to.be.eq(
-          `Unrecognized network ${chainId}.`
-        )
-      }
-    })
-
     it('fails to fetch an unrecognized L2/L3 network', async () => {
       const chainId = 9999
 
@@ -278,17 +116,6 @@ describe('Networks', async () => {
   })
 
   describe('returns correct networks', () => {
-    // todo: this could be a snapshot test
-    it('returns correct L1 networks', () => {
-      const l1NetworksEntries = Object.entries(l1Networks)
-      const l1NetworksKeys = l1NetworksEntries.map(([key]) => key)
-
-      const expected = [1, 1338, 17000, 11155111].map(id => id.toString())
-
-      expect(l1NetworksKeys).to.have.length(expected.length)
-      expect(l1NetworksKeys).to.have.members(expected)
-    })
-
     // todo: this could be a snapshot test
     it('returns correct Arbitrum networks', () => {
       const arbitrumNetworksEntries = Object.entries(arbitrumNetworks)
@@ -305,50 +132,77 @@ describe('Networks', async () => {
 
   describe('getChildrenForNetwork', () => {
     it('returns correct children for ethereum mainnet', () => {
-      const children = getChildrenForNetwork(1).map(c => c.chainID)
+      const children = getChildrenForNetwork(1).map(c => c.chainId)
       expect(children).to.have.members([42161, 42170])
     })
 
     it('returns correct children for arbitrum one', () => {
-      const children = getChildrenForNetwork(42161).map(c => c.chainID)
+      const children = getChildrenForNetwork(42161).map(c => c.chainId)
       expect(children).to.have.members([])
     })
 
     it('returns correct children for arbitrum nova', () => {
-      const children = getChildrenForNetwork(42170).map(c => c.chainID)
+      const children = getChildrenForNetwork(42170).map(c => c.chainId)
       expect(children).to.have.members([])
     })
 
     it('returns correct children for sepolia', () => {
-      const children = getChildrenForNetwork(11155111).map(c => c.chainID)
+      const children = getChildrenForNetwork(11155111).map(c => c.chainId)
       expect(children).to.have.members([421614])
     })
 
     it('returns correct children for arbitrum sepolia', () => {
-      const children = getChildrenForNetwork(421614).map(c => c.chainID)
+      const children = getChildrenForNetwork(421614).map(c => c.chainId)
       expect(children).to.have.members([23011913])
     })
   })
 
-  describe('isParentChain', () => {
+  describe('isParentNetwork', () => {
     it('returns correct value for ethereum mainnet', () => {
-      expect(isParentChain(1)).to.equal(true)
+      expect(isParentNetwork(1)).to.equal(true)
     })
 
     it('returns correct value for arbitrum one', () => {
-      expect(isParentChain(42161)).to.equal(false)
+      expect(isParentNetwork(42161)).to.equal(false)
     })
 
     it('returns correct value for arbitrum nova', () => {
-      expect(isParentChain(42170)).to.equal(false)
+      expect(isParentNetwork(42170)).to.equal(false)
     })
 
     it('returns correct value for sepolia', () => {
-      expect(isParentChain(11155111)).to.equal(true)
+      expect(isParentNetwork(11155111)).to.equal(true)
     })
 
     it('returns correct value for arbitrum sepolia', () => {
-      expect(isParentChain(421614)).to.equal(true)
+      expect(isParentNetwork(421614)).to.equal(true)
+    })
+  })
+
+  describe('getMulticallAddress', () => {
+    it('returns correct value for ethereum mainnet', async () => {
+      const multicall = await getMulticallAddress(1)
+      expect(multicall).to.equal('0x5ba1e12693dc8f9c48aad8770482f4739beed696')
+    })
+
+    it('returns correct value for arbitrum one', async () => {
+      const multicall = await getMulticallAddress(42161)
+      expect(multicall).to.equal('0x842eC2c7D803033Edf55E478F461FC547Bc54EB2')
+    })
+
+    it('returns correct value for arbitrum nova', async () => {
+      const multicall = await getMulticallAddress(42170)
+      expect(multicall).to.equal('0x5e1eE626420A354BbC9a95FeA1BAd4492e3bcB86')
+    })
+
+    it('returns correct value for sepolia', async () => {
+      const multicall = await getMulticallAddress(11155111)
+      expect(multicall).to.equal('0xded9AD2E65F3c4315745dD915Dbe0A4Df61b2320')
+    })
+
+    it('returns correct value for arbitrum sepolia', async () => {
+      const multicall = await getMulticallAddress(421614)
+      expect(multicall).to.equal('0xA115146782b7143fAdB3065D86eACB54c169d092')
     })
   })
 })