diff --git a/composer.json b/composer.json
index b9465af..4416d04 100644
--- a/composer.json
+++ b/composer.json
@@ -17,8 +17,8 @@
   ],
   "require":      {
     "php":                              ">=7.4",
-    "fernleafsystems/apiwrappers-base": "^2.0",
-    "league/oauth2-client":             "^2.0"
+    "fernleafsystems/apiwrappers-base": "^2.1",
+    "league/oauth2-client":             "^2.6"
   },
   "require-dev":  {
   },
diff --git a/src/Api.php b/src/Api.php
index 3b813e1..9f2787c 100644
--- a/src/Api.php
+++ b/src/Api.php
@@ -53,15 +53,11 @@ protected function getResponseDataPayloadKey() :string {
 		return $this->getRequestDataPayloadKey();
 	}
 
-	/**
-	 * @return array|null
-	 */
-	public function getCoreResponseData() {
+	public function getCoreResponseData() :?array {
 		$data = null;
 		if ( $this->isLastRequestSuccess() ) {
 			$key = $this->getResponseDataPayloadKey();
-			$decoded = $this->getDecodedResponseBody();
-			$data = empty( $key ) ? $decoded : $decoded[ $key ];
+			$data = empty( $key ) ? $this->getDecodedResponseBody() : $this->getDecodedResponseBody()[ $key ];
 		}
 		return $data;
 	}
@@ -101,17 +97,9 @@ protected function preSendVerification() {
 		}
 	}
 
-	/**
-	 * @return EntityVO|mixed|null
-	 */
-	public function sendRequestWithVoResponse() {
+	public function sendRequestWithVoResponse() :?EntityVO {
 		$data = $this->req()->getCoreResponseData();
-
-		$VO = null;
-		if ( !empty( $data ) ) {
-			$VO = $this->getVO()->applyFromArray( $data );
-		}
-		return $VO;
+		return empty( $data ) ? null : $this->getVO()->applyFromArray( $data );
 	}
 
 	/**
diff --git a/src/Entities/BankTransactionExplanation/Create.php b/src/Entities/BankTransactionExplanation/Create.php
index cf772f2..4d09699 100644
--- a/src/Entities/BankTransactionExplanation/Create.php
+++ b/src/Entities/BankTransactionExplanation/Create.php
@@ -38,35 +38,35 @@ public function setAssociatedPaidTo( $sAssociatedTo, $sAssociatedId ) {
 	 */
 	public function setBankAccount( $oBankAccount ) {
 		return $this->removeRequestDataItem( 'bank_transaction' )
-					->setRequestDataItem( 'bank_account', $oBankAccount->getUri() );
+					->setRequestDataItem( 'bank_account', $oBankAccount->url );
 	}
 
 	/**
-	 * @param BankTransactionVO $oBankTxn
+	 * @param BankTransactionVO $txn
 	 * @return $this
 	 */
-	public function setBankTxn( $oBankTxn ) {
+	public function setBankTxn( $txn ) {
 		return $this->removeRequestDataItem( 'bank_account' )
-					->setRequestDataItem( 'bank_transaction', $oBankTxn->getUri() )
-					->setDatedOn( $oBankTxn->getDatedOn() );
+					->setRequestDataItem( 'bank_transaction', $txn->url )
+					->setDatedOn( $txn->dated_on );
 	}
 
 	/**
-	 * @param BillVO $oBill
+	 * @param BillVO $bill
 	 * @return $this
 	 */
-	public function setBillPaid( $oBill ) {
+	public function setBillPaid( $bill ) {
 		return $this->removeRequestDataItem( 'paid_invoice' )
-					->setAssociatedPaidTo( 'bill', $oBill->getUri() );
+					->setAssociatedPaidTo( 'bill', $bill->url );
 	}
 
 	/**
-	 * @param InvoiceVO $oInvoice
+	 * @param InvoiceVO $invoice
 	 * @return $this
 	 */
-	public function setInvoicePaid( $oInvoice ) {
+	public function setInvoicePaid( $invoice ) {
 		return $this->removeRequestDataItem( 'paid_bill' )
-					->setAssociatedPaidTo( 'invoice', $oInvoice->getUri() );
+					->setAssociatedPaidTo( 'invoice', $invoice->url );
 	}
 
 	/**
diff --git a/src/Entities/BankTransactionExplanation/CreateTransferToAnotherAccount.php b/src/Entities/BankTransactionExplanation/CreateTransferToAnotherAccount.php
index c5e9c87..98b793c 100644
--- a/src/Entities/BankTransactionExplanation/CreateTransferToAnotherAccount.php
+++ b/src/Entities/BankTransactionExplanation/CreateTransferToAnotherAccount.php
@@ -7,10 +7,9 @@
 class CreateTransferToAnotherAccount extends Create {
 
 	/**
-	 * @param BankAccountVO $oBankAccount
 	 * @return $this
 	 */
-	public function setTargetBankAccount( $oBankAccount ) {
-		return $this->setRequestDataItem( 'transfer_bank_account', $oBankAccount->getUri() );
+	public function setTargetBankAccount( BankAccountVO $bankAccount ) {
+		return $this->setRequestDataItem( 'transfer_bank_account', $bankAccount->url );
 	}
 }
\ No newline at end of file
diff --git a/src/Entities/BankTransactionExplanation/RetrieveBulk.php b/src/Entities/BankTransactionExplanation/RetrieveBulk.php
index 16adf12..e0e171b 100644
--- a/src/Entities/BankTransactionExplanation/RetrieveBulk.php
+++ b/src/Entities/BankTransactionExplanation/RetrieveBulk.php
@@ -14,6 +14,6 @@ class RetrieveBulk extends RetrieveBulkBase {
 	 * @return $this
 	 */
 	public function setBankAccount( $oBankAccount ) {
-		return $this->setRequestDataItem( 'bank_account', $oBankAccount->getUri() );
+		return $this->setRequestDataItem( 'bank_account', $oBankAccount->url );
 	}
 }
\ No newline at end of file
diff --git a/src/Entities/BankTransactions/BankTransactionsIterator.php b/src/Entities/BankTransactions/BankTransactionsIterator.php
index 0138880..00a7cfa 100644
--- a/src/Entities/BankTransactions/BankTransactionsIterator.php
+++ b/src/Entities/BankTransactions/BankTransactionsIterator.php
@@ -6,13 +6,9 @@
 
 class BankTransactionsIterator extends Entities\Common\CommonIterator {
 
-	/**
-	 * @param Entities\BankAccounts\BankAccountVO $oBankAccount
-	 * @return $this
-	 */
-	public function filterByBankAccount( $oBankAccount ) {
+	public function filterByBankAccount( Entities\BankAccounts\BankAccountVO $bankAccount ) :self {
 		$this->getRetriever()
-			 ->setRequestDataItem( 'bank_account', $oBankAccount->getUri() );
+			 ->setRequestDataItem( 'bank_account', $bankAccount->url );
 		return $this;
 	}
 
diff --git a/src/Entities/BankTransactions/Find.php b/src/Entities/BankTransactions/Find.php
index b3539f5..69c414d 100644
--- a/src/Entities/BankTransactions/Find.php
+++ b/src/Entities/BankTransactions/Find.php
@@ -7,11 +7,11 @@
 class Find extends RetrieveBulk {
 
 	/**
-	 * @param BankAccountVO $oBankAccount
+	 * @param BankAccountVO $bankAccount
 	 * @return $this
 	 */
-	public function setBankAccount( $oBankAccount ) {
-		return $this->setRequestDataItem( 'bank_account', $oBankAccount->getUri() );
+	public function setBankAccount( $bankAccount ) {
+		return $this->setRequestDataItem( 'bank_account', $bankAccount->url );
 	}
 
 	/**
diff --git a/src/Entities/BankTransactions/UploadStatement.php b/src/Entities/BankTransactions/UploadStatement.php
index d665384..5b66273 100644
--- a/src/Entities/BankTransactions/UploadStatement.php
+++ b/src/Entities/BankTransactions/UploadStatement.php
@@ -58,7 +58,7 @@ protected function getUrlEndpoint() :string {
 	 * @return $this
 	 */
 	public function setBankAccount( $oBankAccount ) {
-		return $this->setRequestQueryDataItem( 'bank_account', $oBankAccount->getUri() );
+		return $this->setRequestQueryDataItem( 'bank_account', $oBankAccount->url );
 	}
 
 	/**
diff --git a/src/Entities/Bills/BillsIterator.php b/src/Entities/Bills/BillsIterator.php
index 566d1cd..5a48dc8 100644
--- a/src/Entities/Bills/BillsIterator.php
+++ b/src/Entities/Bills/BillsIterator.php
@@ -12,7 +12,7 @@ class BillsIterator extends Entities\Common\CommonIterator {
 	 */
 	public function filterByContact( $contact ) {
 		$this->getRetriever()
-			 ->setRequestDataItem( 'contact', $contact->getUri() );
+			 ->setRequestDataItem( 'contact', $contact->url );
 		return $this;
 	}
 
diff --git a/src/Entities/Bills/Create.php b/src/Entities/Bills/Create.php
index 0c6df41..66db27e 100644
--- a/src/Entities/Bills/Create.php
+++ b/src/Entities/Bills/Create.php
@@ -25,7 +25,7 @@ public function addBillItem( BillItemVO $item, bool $merge = true ) :self {
 	}
 
 	public function setCategory( CategoryVO $category ) :self {
-		return $this->setRequestDataItem( 'category', $category->getUri() );
+		return $this->setRequestDataItem( 'category', $category->url );
 	}
 
 	/**
@@ -47,7 +47,7 @@ public function setComment( $comment ) :self {
 	 * @param ContactVO $contact
 	 */
 	public function setContact( $contact ) :self {
-		return $this->setRequestDataItem( 'contact', $contact->getUri() );
+		return $this->setRequestDataItem( 'contact', $contact->url );
 	}
 
 	/**
diff --git a/src/Entities/Categories/Retrieve.php b/src/Entities/Categories/Retrieve.php
index 62db655..b1dbcf9 100644
--- a/src/Entities/Categories/Retrieve.php
+++ b/src/Entities/Categories/Retrieve.php
@@ -4,37 +4,26 @@
 
 class Retrieve extends Base {
 
-	/**
-	 * @return bool
-	 */
-	public function exists() {
-		return !is_null( $this->retrieve() );
+	public function exists() :bool {
+		return $this->retrieve() !== null;
 	}
 
-	/**
-	 * @return CategoryVO
-	 */
-	public function retrieve() {
+	public function retrieve() :?CategoryVO {
 		return $this->sendRequestWithVoResponse();
 	}
 
-	/**
-	 * @return CategoryVO|mixed|null
-	 */
-	public function sendRequestWithVoResponse() {
+	public function sendRequestWithVoResponse() :?CategoryVO {
 		try {
-			$aData = $this->send()
-						  ->getCoreResponseData();
+			$data = $this->send()->getCoreResponseData();
 		}
 		catch ( \Exception $e ) {
 		}
 
 		$VO = null;
-		if ( !empty( $aData ) && is_array( $aData ) ) {
-			foreach ( $aData as $sCatType => $aCategory ) {
+		if ( !empty( $data ) && is_array( $data ) ) {
+			foreach ( $data as $sCatType => $aCategory ) {
 				if ( $aCategory[ 'nominal_code' ] == $this->entity_id ) {
-					$VO = $this->getVO()
-							   ->applyFromArray( $aCategory );
+					$VO = $this->getVO()->applyFromArray( $aCategory );
 				}
 			}
 		}
@@ -50,9 +39,6 @@ public function setEntityId( $id ) :self {
 		return $this;
 	}
 
-	/**
-	 * @throws \Exception
-	 */
 	protected function preSendVerification() {
 		parent::preSendVerification();
 		if ( !$this->hasEntityId() ) {
diff --git a/src/Entities/Contacts/Base.php b/src/Entities/Contacts/Base.php
index 0451085..d0ff5ad 100644
--- a/src/Entities/Contacts/Base.php
+++ b/src/Entities/Contacts/Base.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare( strict_types=1 );
 
 namespace FernleafSystems\ApiWrappers\Freeagent\Entities\Contacts;
 
diff --git a/src/Entities/Contacts/ContactVO.php b/src/Entities/Contacts/ContactVO.php
index 2724ca9..694dcf2 100644
--- a/src/Entities/Contacts/ContactVO.php
+++ b/src/Entities/Contacts/ContactVO.php
@@ -10,82 +10,26 @@
  * @property string $first_name
  * @property string $last_name
  * @property string $organisation_name
- * @property string $country
- * @property string $sales_tax_registration_number
  * @property string $charge_sales_tax - 'Auto', 'Always', 'Never'
+ * @property string $sales_tax_registration_number
  * @property string $status
+ * @property string $billing_email
+ * @property string $phone_number
+ * @property string $mobile
+ * @property string $address1
+ * @property string $address2
+ * @property string $address3
+ * @property string $town
+ * @property string $region
+ * @property string $postcode
+ * @property string $country
+ * @property bool   $uses_contact_invoice_sequence
  */
 class ContactVO extends EntityVO {
 
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getChargeSalesTax() {
-		return $this->charge_sales_tax;
-	}
-
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getCountry() {
-		return $this->country;
-	}
-
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getEmail() {
-		return $this->email;
-	}
-
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getFirstName() {
-		return $this->first_name;
-	}
-
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getLastName() {
-		return $this->last_name;
-	}
-
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getOrganisationName() {
-		return $this->organisation_name;
-	}
-
-	/**
-	 * @return string
-	 * @deprecated
-	 */
-	public function getSalesTaxRegistrationNumber() {
-		return $this->sales_tax_registration_number;
-	}
-
-	/**
-	 * @return string 'Active', 'Hidden'
-	 * @deprecated
-	 */
-	public function getStatus() {
-		return $this->status;
-	}
-
-	/**
-	 * @return bool
-	 * @deprecated
-	 */
-	public function hasSalesTaxRegistrationNumber() {
-		return !empty( $this->sales_tax_registration_number );
-	}
+	public const CHARGE_SALES_TAX_AUTO = 'Auto';
+	public const CHARGE_SALES_TAX_ALWAYS = 'Always';
+	public const CHARGE_SALES_TAX_NEVER = 'Never';
+	public const STATUS_ACTIVE = 'Active';
+	public const STATUS_HIDDEN = 'Hidden';
 }
\ No newline at end of file
diff --git a/src/Entities/Contacts/ContactsIterator.php b/src/Entities/Contacts/ContactsIterator.php
index c3a7ace..111dfef 100644
--- a/src/Entities/Contacts/ContactsIterator.php
+++ b/src/Entities/Contacts/ContactsIterator.php
@@ -7,12 +7,12 @@
 class ContactsIterator extends Entities\Common\CommonIterator {
 
 	/**
-	 * @param Entities\Contacts\ContactVO $oContact
+	 * @param Entities\Contacts\ContactVO $contact
 	 * @return $this
 	 */
-	public function filterByContact( $oContact ) {
+	public function filterByContact( $contact ) {
 		$this->getRetriever()
-			 ->setRequestDataItem( 'contact', $oContact->getUri() );
+			 ->setRequestDataItem( 'contact', $contact->url );
 		return $this;
 	}
 
diff --git a/src/Entities/Contacts/ContactsTrait.php b/src/Entities/Contacts/ContactsTrait.php
index 8df1435..fe0141f 100644
--- a/src/Entities/Contacts/ContactsTrait.php
+++ b/src/Entities/Contacts/ContactsTrait.php
@@ -4,9 +4,6 @@
 
 trait ContactsTrait {
 
-	/**
-	 * @return string
-	 */
 	protected function getApiEndpoint() :string {
 		return 'contacts';
 	}
diff --git a/src/Entities/Contacts/Create.php b/src/Entities/Contacts/Create.php
index 4d3be00..01e8c98 100644
--- a/src/Entities/Contacts/Create.php
+++ b/src/Entities/Contacts/Create.php
@@ -3,24 +3,18 @@
 namespace FernleafSystems\ApiWrappers\Freeagent\Entities\Contacts;
 
 use FernleafSystems\ApiWrappers\Freeagent\Entities\Common\Constants;
-use FernleafSystems\ApiWrappers\Freeagent\Entities\Common\EntityVO;
 
 class Create extends Base {
 
-	const REQUEST_METHOD = 'post';
+	public const REQUEST_METHOD = 'post';
 
-	/**
-	 * @param array $aData
-	 * @return ContactVO|null
-	 */
-	public function create( $aData = [] ) {
+	public function create( array $data = [] ) :?ContactVO {
 		/** @var ContactVO $contact */
-		$contact = $this->setRequestData( $aData, true )
-						->sendRequestWithVoResponse();
+		$contact = $this->setRequestData( $data )->sendRequestWithVoResponse();
 
 		{ // Fix for FreeAgent API broken country names. Find which FA Country corresponds to the requested country.
 			$requestedCountry = $this->getRequestDataItem( 'country' );
-			if ( $contact instanceof EntityVO && $contact->country !== $requestedCountry ) {
+			if ( $contact instanceof ContactVO && $contact->country !== $requestedCountry ) {
 				foreach ( Constants::FREEAGENT_EU_COUNTRIES as $faCountry => $alternatives ) {
 					if ( in_array( strtolower( $requestedCountry ), array_map( 'strtolower', $alternatives ) ) ) {
 						$contact = $this->setAddress_Country( $faCountry )
@@ -34,14 +28,18 @@ public function create( $aData = [] ) {
 		return $contact;
 	}
 
+	public function createFromVO( ContactVO $contact ) :?ContactVO {
+		return $this->create( $contact->getRawData() );
+	}
+
 	/**
 	 * @throws \Exception
 	 */
 	protected function preSendVerification() {
 		parent::preSendVerification();
 
-		$sOrganisationName = $this->getRequestDataItem( 'organisation_name' );
-		if ( empty( $sOrganisationName ) ) {
+		$orgName = $this->getRequestDataItem( 'organisation_name' );
+		if ( empty( $orgName ) ) {
 			$firstName = $this->getRequestDataItem( 'first_name' );
 			if ( empty( $firstName ) ) {
 				throw new \Exception( sprintf( 'Field "%s" cannot be empty.', 'first_name' ) );
@@ -53,118 +51,71 @@ protected function preSendVerification() {
 		}
 	}
 
-	/**
-	 * @param string $value
-	 * @return $this
-	 */
-	public function setAddress_Country( $value ) {
+	public function setAddress_Country( string $value ) :self {
 		return $this->setRequestDataItem( 'country', $value );
 	}
 
-	/**
-	 * @param string $sValue
-	 * @param int    $nLine
-	 * @return $this
-	 */
-	public function setAddress_Line( $sValue, $nLine = 1 ) {
-		return $this->setRequestDataItem( 'address'.$nLine, $sValue );
+	public function setAddress_Line( string $value, int $line = 1 ) :self {
+		return $this->setRequestDataItem( 'address'.max( min( $line, 3 ), 1 ), $value );
 	}
 
-	/**
-	 * @param string $sValue
-	 * @return $this
-	 */
-	public function setAddress_PostalCode( $sValue ) {
-		return $this->setRequestDataItem( 'postcode', $sValue );
+	public function setAddress_PostalCode( string $value ) :self {
+		return $this->setRequestDataItem( 'postcode', $value );
 	}
 
-	/**
-	 * @param string $sValue
-	 * @return $this
-	 */
-	public function setAddress_Region( $sValue ) {
-		return $this->setRequestDataItem( 'region', $sValue );
+	public function setAddress_Region( string $value ) :self {
+		return $this->setRequestDataItem( 'region', $value );
 	}
 
-	/**
-	 * @param string $sValue
-	 * @return $this
-	 */
-	public function setAddress_Town( $sValue ) {
-		return $this->setRequestDataItem( 'town', $sValue );
+	public function setAddress_Town( string $value ) :self {
+		return $this->setRequestDataItem( 'town', $value );
 	}
 
-	/**
-	 * @param string $email - will set both account email and billing email
-	 * @return $this
-	 */
-	public function setEmail( $email ) {
+	public function setEmail( string $email ) :self {
 		return $this->setRequestDataItem( 'email', $email )
 					->setEmailForBilling( $email );
 	}
 
-	/**
-	 * @param string $email
-	 * @return $this
-	 */
-	public function setEmailForBilling( $email ) {
+	public function setEmailForBilling( string $email ) :self {
 		return $this->setRequestDataItem( 'billing_email', $email );
 	}
 
-	/**
-	 * @param string $sName
-	 * @return $this
-	 */
-	public function setFirstName( $sName ) {
-		return $this->setRequestDataItem( 'first_name', $sName );
+	public function setFirstName( string $name ) :self {
+		return $this->setRequestDataItem( 'first_name', $name );
 	}
 
-	/**
-	 * @param string $name
-	 * @return $this
-	 */
-	public function setLastName( $name ) {
+	public function setLastName( string $name ) :self {
 		return $this->setRequestDataItem( 'last_name', $name );
 	}
 
-	/**
-	 * @param string $name
-	 * @return $this
-	 */
-	public function setOrganisationName( $name ) {
+	public function setOrganisationName( string $name ) :self {
 		return $this->setRequestDataItem( 'organisation_name', $name );
 	}
 
-	/**
-	 * @param string $sAutoAlwaysNever
-	 * @return $this
-	 */
-	public function setSalesTaxCharge( $sAutoAlwaysNever ) {
-		return $this->setRequestDataItem( 'charge_sales_tax', $sAutoAlwaysNever );
+	public function setSalesTaxCharge( string $charge ) :self {
+		if ( in_array( $charge, [
+			ContactVO::CHARGE_SALES_TAX_ALWAYS,
+			ContactVO::CHARGE_SALES_TAX_AUTO,
+			ContactVO::CHARGE_SALES_TAX_NEVER
+		] ) ) {
+			$this->setRequestDataItem( 'charge_sales_tax', $charge );
+		}
+		return $this;
 	}
 
-	/**
-	 * @param string $sRegistrationNumber
-	 * @return $this
-	 */
-	public function setSalesTaxNumber( $sRegistrationNumber ) {
-		return $this->setRequestDataItem( 'sales_tax_registration_number', $sRegistrationNumber );
+	public function setSalesTaxNumber( string $taxRegistrationNumber ) :self {
+		return $this->setRequestDataItem( 'sales_tax_registration_number', $taxRegistrationNumber );
 	}
 
-	/**
-	 * @param string $sStatus
-	 * @return $this
-	 */
-	public function setStatus( $sStatus ) {
-		return $this->setRequestDataItem( 'status', ucfirst( strtolower( $sStatus ) ) );
+	public function setStatus( string $status ) :self {
+		if ( in_array( $status, [ ContactVO::STATUS_HIDDEN, ContactVO::STATUS_ACTIVE ] ) ) {
+			$this->setRequestDataItem( 'status', $status );
+		}
+		return $this;
 	}
 
-	/**
-	 * @param bool $bContactLevel
-	 * @return $this
-	 */
-	public function setUseContactLevelInvoiceSequence( $bContactLevel ) {
-		return $this->setRequestDataItem( 'uses_contact_invoice_sequence', $bContactLevel );
+	public function setUseContactLevelInvoiceSequence( bool $contactLevel ) :self {
+		return $this->setRequestDataItem( 'uses_contact_invoice_sequence', $contactLevel );
 	}
 
 	protected function getCriticalRequestItems() :array {
diff --git a/src/Entities/Contacts/Delete.php b/src/Entities/Contacts/Delete.php
index b2698e2..adf9166 100644
--- a/src/Entities/Contacts/Delete.php
+++ b/src/Entities/Contacts/Delete.php
@@ -4,15 +4,11 @@
 
 class Delete extends Base {
 
-	const REQUEST_METHOD = 'delete';
+	public const REQUEST_METHOD = 'delete';
 
-	/**
-	 * @param int $nContactId
-	 * @return $this
-	 */
-	public function delete( $nContactId = 0 ) {
-		if ( is_int( $nContactId ) && $nContactId > 0 ) {
-			$this->setEntityId( $nContactId );
+	public function delete( $contactId = 0 ) :self {
+		if ( is_int( $contactId ) && $contactId > 0 ) {
+			$this->setEntityId( $contactId );
 		}
 		return $this->send();
 	}
diff --git a/src/Entities/Contacts/Finder.php b/src/Entities/Contacts/Finder.php
index d436d21..c62964c 100644
--- a/src/Entities/Contacts/Finder.php
+++ b/src/Entities/Contacts/Finder.php
@@ -5,17 +5,17 @@
 class Finder extends ContactsIterator {
 
 	/**
-	 * @param string $sEmail
+	 * @param string $email
 	 * @return ContactVO|null
 	 */
-	public function findByEmail( $sEmail ) {
-		$oTheOne = null;
-		foreach ( $this as $oContact ) {
-			if ( strcasecmp( $oContact->email, $sEmail ) === 0 ) {
-				$oTheOne = $oContact;
+	public function findByEmail( $email ) {
+		$theOne = null;
+		foreach ( $this as $contact ) {
+			if ( strcasecmp( $contact->email, $email ) === 0 ) {
+				$theOne = $contact;
 				break;
 			}
 		}
-		return $oTheOne;
+		return $theOne;
 	}
 }
\ No newline at end of file
diff --git a/src/Entities/Contacts/Hide.php b/src/Entities/Contacts/Hide.php
index 35e9566..f45ac73 100644
--- a/src/Entities/Contacts/Hide.php
+++ b/src/Entities/Contacts/Hide.php
@@ -1,14 +1,10 @@
-<?php
+<?php declare( strict_types=1 );
 
 namespace FernleafSystems\ApiWrappers\Freeagent\Entities\Contacts;
 
 class Hide extends Update {
 
-	/**
-	 * @return ContactVO|null
-	 */
-	public function hide() {
-		return $this->setStatus( 'Hidden' )
-					->update();
+	public function hide() :?ContactVO {
+		return $this->setStatus( 'Hidden' )->update();
 	}
 }
\ No newline at end of file
diff --git a/src/Entities/Contacts/Retrieve.php b/src/Entities/Contacts/Retrieve.php
index cff0002..ce3367b 100644
--- a/src/Entities/Contacts/Retrieve.php
+++ b/src/Entities/Contacts/Retrieve.php
@@ -4,17 +4,11 @@
 
 class Retrieve extends Base {
 
-	/**
-	 * @return bool
-	 */
-	public function exists() {
-		return !is_null( $this->retrieve() );
+	public function exists() :bool {
+		return $this->retrieve() !== null;
 	}
 
-	/**
-	 * @return ContactVO
-	 */
-	public function retrieve() {
+	public function retrieve() :?ContactVO {
 		return $this->sendRequestWithVoResponse();
 	}
 
diff --git a/src/Entities/Contacts/Update.php b/src/Entities/Contacts/Update.php
index 6300e89..7e1944b 100644
--- a/src/Entities/Contacts/Update.php
+++ b/src/Entities/Contacts/Update.php
@@ -16,12 +16,8 @@ protected function preSendVerification() {
 		}
 	}
 
-	/**
-	 * @param array $aUpdateData
-	 * @return ContactVO|null
-	 */
-	public function update( $aUpdateData = [] ) {
-		return $this->create( $aUpdateData );
+	public function update( array $data = [] ) :?ContactVO {
+		return $this->create( $data );
 	}
 
 	protected function getCriticalRequestItems() :array {
diff --git a/src/Entities/Invoices/Create.php b/src/Entities/Invoices/Create.php
index f9b4e86..b097957 100644
--- a/src/Entities/Invoices/Create.php
+++ b/src/Entities/Invoices/Create.php
@@ -49,7 +49,7 @@ public function setComments( $comments ) :self {
 	}
 
 	public function setContact( ContactVO $contact ) :self {
-		return $this->setRequestDataItem( 'contact', $contact->getUri() );
+		return $this->setRequestDataItem( 'contact', $contact->url );
 	}
 
 	/**
diff --git a/src/Entities/Invoices/InvoicesIterator.php b/src/Entities/Invoices/InvoicesIterator.php
index 0476ddd..d8b349d 100644
--- a/src/Entities/Invoices/InvoicesIterator.php
+++ b/src/Entities/Invoices/InvoicesIterator.php
@@ -12,7 +12,7 @@ class InvoicesIterator extends Entities\Common\CommonIterator {
 	 */
 	public function filterByContact( $contact ) {
 		$this->getRetriever()
-			 ->setRequestDataItem( 'contact', $contact->getUri() );
+			 ->setRequestDataItem( 'contact', $contact->url );
 		return $this;
 	}