fix

Pusher.php

@@ -109,11 +109,7 @@ public function flush()
      */
     public function listen($channels, $callback = null)
     {
-        $endpoint = $this->makeEndpoint(array_merge($this->serverOptions, $this->listenServerOptions));
-        if (substr($endpoint, -1) != '/') {
-            $endpoint .= '/';
-        }
-        $endpoint .= implode($this->channelSplitter, (array)$channels);
+        $endpoint = $this->getListenerHost($channels);
 
         $response = $this->client->get($endpoint, [
             'stream' => true
@@ -129,6 +125,17 @@ public function listen($channels, $callback = null)
         }
     }
 
+    public function getListenerHost($channels)
+    {
+        $endpoint = $this->makeEndpoint(array_merge($this->serverOptions, $this->listenServerOptions));
+        if (substr($endpoint, -1) != '/') {
+            $endpoint .= '/';
+        }
+        $endpoint .= implode($this->channelSplitter, (array)$channels);
+
+        return $endpoint;
+    }
+
     /**
      *
      * @param $serverOptions array of server options

composer.json

@@ -12,7 +12,7 @@
     ],
     "require": {
         "php": ">=7.2",
-        "yiisoft/yii2": "*",
+        "yiisoft/yii2": "^2.0",
         "guzzlehttp/guzzle": "^6.2"
     },
     "autoload": {