diff --git a/cli.js b/cli.js
index 6ff38d0..e94fedd 100755
--- a/cli.js
+++ b/cli.js
@@ -26,6 +26,10 @@ const {
 			type: 'string',
 			short: 'l',
 		},
+		'their-leitstelle': {
+			type: 'string',
+			short: 'L',
+		},
 		'endpoint': {
 			type: 'string',
 			short: 'e',
@@ -62,6 +66,9 @@ Options:
 	                              client, a bit like an HTTP User-Agent. Must be agreed-
 	                              upon with the provider of the VDV-453 API.
 	                              Default: $VDV_453_LEITSTELLE
+	--their-leitstelle        -L  VDV-453 Leitstellenkennung of the server. Must be agreed-
+	                              upon with the provider of the VDV-453 API.
+	                              Default: $VDV_453_THEIR_LEITSTELLE
 	--endpoint                -e  HTTP(S) URL of the VDV-453 API.
 	                              Default: $VDV_453_ENDPOINT
 	--port                    -p  Port to listen on. VDV-453 requires the *client* to run
@@ -123,6 +130,13 @@ if ('leitstelle' in flags) {
 } else {
 	abortWithError('missing/empty --leitstelle/-l/$VDV_453_LEITSTELLE')
 }
+if ('their-leitstelle' in flags) {
+	cfg.theirLeitstelle = flags['their-leitstelle']
+} else if ('VDV_453_THEIR_LEITSTELLE' in process.env) {
+	cfg.theirLeitstelle = process.env.VDV_453_THEIR_LEITSTELLE
+} else {
+	abortWithError('missing/empty --their-leitstelle/-L/$VDV_453_THEIR_LEITSTELLE')
+}
 
 if ('endpoint' in flags) {
 	cfg.endpoint = flags.endpoint
diff --git a/index.js b/index.js
index 0c656bd..b47ed9c 100644
--- a/index.js
+++ b/index.js
@@ -6,11 +6,13 @@ import {connectToNats, JSONCodec} from './lib/nats.js'
 const sendVdv453DataToNats = async (cfg, opt = {}) => {
 	const {
 		leitstelle,
+		theirLeitstelle,
 		endpoint,
 		port,
 		subscriptions,
 	} = cfg
 	ok(leitstelle, 'missing/empty cfg.leitstelle')
+	ok(theirLeitstelle, 'missing/empty cfg.theirLeitstelle')
 	ok(endpoint, 'missing/empty cfg.endpoint')
 	ok(Number.isInteger(port), 'cfg.port must be an integer')
 	ok(Array.isArray(subscriptions), 'cfg.subscriptions must be an array')
@@ -37,6 +39,7 @@ const sendVdv453DataToNats = async (cfg, opt = {}) => {
 	const client = createClient({
 		...vdv453ClientOpts,
 		leitstelle,
+		theirLeitstelle,
 		endpoint,
 	})
 	const {
diff --git a/package.json b/package.json
index a9b43be..6745e78 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,7 @@
 	"dependencies": {
 		"luxon": "^3.4.4",
 		"nats": "^2.22.0",
-		"vdv-453-client": "^1.0.0"
+		"vdv-453-client": "^2.0.0-alpha.0"
 	},
 	"devDependencies": {
 		"@eslint/js": "^9.0.0",
diff --git a/readme.md b/readme.md
index f1110db..a2a9dca 100644
--- a/readme.md
+++ b/readme.md
@@ -20,20 +20,22 @@ Please note the limitations imposed by the underlying library [`vdv-453-client`]
 > 
 > *Note:* This client supports neither the latest 2.x spec versions ([VDV-453 v2.6.1](https://www.vdv.de/vdv-schrift-453-v2.6.1-de.pdfx?forced=true)/[VDV-454 v2.2.1](https://www.vdv.de/454v2.2.1-sd.pdfx?forced=true)) nor the latest 3.x spec versions ([VDV-453 v3.0](https://www.vdv.de/downloads/4337/453v3.0%20SDS/forced)/[VDV-454 v3.0](https://www.vdv.de/downloads/4336/454v3.0%20SDS/forced)).
 
-With the organisation providing the VDV 453 API, you will have to agree upon a *Leitstellenkennung*, which is a bit like an HTTP User-Agent:
+With the organisation providing the VDV 453 API, you will have to agree upon a *Leitstellenkennung* you'll use, which is a bit like an HTTP User-Agent:
 
 > 6.1.3 Leitstellenkennung
 >
 > Um Botschaften verschiedener Kommunikationspartner innerhalb eines Dienstes unterscheiden zu können, enthält jede Nachricht eine eindeutige Leitstellenkennung (Attribut `Sender`) des nachfragenden Systems. […]
 
-Then, configure access to the VDV-453 system and run the adapter:
+Then, configure access to the VDV-453 system, and run the adapter:
 
 ```bash
 send-vdv-453-data-to-nats \
 	# must have a trailing `/`
 	--endpoint 'http://example.org:1234/api/' \
-	# as agreed-upon between the VDV-453 API's operator and you
-	--leitstelle '…'
+	# your Leitstellenkennung, as agreed-upon between the VDV-453 API's operator and you
+	--leitstelle '…' \
+	# their Leitstellenkennung, as agreed-upon between the VDV-453 API's operator and you
+	--their-leitstelle '…'
 ```
 
 
@@ -50,6 +52,9 @@ Options:
 	                              client, a bit like an HTTP User-Agent. Must be agreed-
 	                              upon with the provider of the VDV-453 API.
 	                              Default: $VDV_453_LEITSTELLE
+	--their-leitstelle        -L  VDV-453 Leitstellenkennung of the server. Must be agreed-
+	                              upon with the provider of the VDV-453 API.
+	                              Default: $VDV_453_THEIR_LEITSTELLE
 	--endpoint                -e  HTTP(S) URL of the VDV-453 API.
 	                              Default: $VDV_453_ENDPOINT
 	--port                    -p  Port to listen on. VDV-453 requires the *client* to run