diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2292a0f..7c7baaa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [4.0.4] - 2025-06-06
+
+- Changing async run wrapper to use explicit arguments to fix multichannel tests in aladdin
+
 ## [4.0.3] - 2025-06-06
 
 - Fixed microphone transcription tests not working after adding multichan dz support
diff --git a/VERSION b/VERSION
index aa31e71..7d666cb 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.0.3
\ No newline at end of file
+4.0.4
\ No newline at end of file
diff --git a/examples/transcribe_from_youtube/youtube_transcribe.py b/examples/transcribe_from_youtube/youtube_transcribe.py
index 4024e81..9af57c3 100644
--- a/examples/transcribe_from_youtube/youtube_transcribe.py
+++ b/examples/transcribe_from_youtube/youtube_transcribe.py
@@ -52,7 +52,11 @@ def main(args):
 
     def run(stream):
         try:
-            api.run_synchronously(stream, transcription_config, AudioSettings())
+            api.run_synchronously(
+                stream=stream,
+                transcription_config=transcription_config,
+                audio_settings=AudioSettings(),
+            )
         except KeyboardInterrupt:
             # Gracefully handle Ctrl-C, else we get a huge stack-trace.
             LOGGER.warning("Keyboard interrupt received.")
diff --git a/speechmatics/cli.py b/speechmatics/cli.py
index e34d4a1..51b77d5 100755
--- a/speechmatics/cli.py
+++ b/speechmatics/cli.py
@@ -810,20 +810,14 @@ def rt_main(args):
 
     def run(stream=None, channel_stream_pairs=None):
         try:
-            # Pass in either stream or channel_stream_pairs depending on what != None
-            # Dynamically construct the args based on the input
-            args_list = [transcription_config]
-            if stream is not None:
-                args_list.append(stream)
-            elif channel_stream_pairs is not None:
-                args_list.append(None)  # This skips the stream argument
-                args_list.append(channel_stream_pairs)
-            else:
+            if stream is None and channel_stream_pairs is None:
                 raise SystemExit(
                     "Neither stream nor channel_stream_pairs were provided."
                 )
             api.run_synchronously(
-                *args_list,
+                transcription_config=transcription_config,
+                stream=stream,
+                channel_stream_pairs=channel_stream_pairs,
                 audio_settings=get_audio_settings(args),
                 from_cli=True,
                 extra_headers=extra_headers,
diff --git a/speechmatics/client.py b/speechmatics/client.py
index 93e3eaa..915a5f3 100644
--- a/speechmatics/client.py
+++ b/speechmatics/client.py
@@ -553,6 +553,10 @@ async def run(
             consumer/producer tasks.
         """
         if channel_stream_pairs:
+            if not isinstance(channel_stream_pairs, dict):
+                raise TypeError(
+                    "channel_stream_pairs must be a dict of {str: file-like or path}"
+                )
             opened_streams = {}
             self._stream_exits = AsyncExitStack()
             for channel_name, path in channel_stream_pairs.items():
@@ -569,6 +573,9 @@ async def run(
         await self._init_synchronization_primitives()
         if extra_headers is None:
             extra_headers = {}
+        else:
+            if not isinstance(extra_headers, dict):
+                raise TypeError("extra_headers must be a dict")
         if audio_settings is None:
             audio_settings = AudioSettings()
         if (
@@ -632,13 +639,35 @@ def stop(self):
         """
         self._session_needs_closing = True
 
-    def run_synchronously(self, *args, timeout=None, **kwargs):
+    def run_synchronously(
+        self,
+        transcription_config: TranscriptionConfig,
+        *,
+        stream: Optional[Any] = None,
+        channel_stream_pairs: Optional[Dict[str, Any]] = None,
+        audio_settings: Optional[AudioSettings] = None,
+        from_cli: bool = False,
+        extra_headers: Optional[Dict] = None,
+        timeout=None,
+    ):
         """
         Run the transcription synchronously.
         :raises asyncio.TimeoutError: If the given timeout is exceeded.
         """
         # pylint: disable=no-value-for-parameter
-        asyncio.run(asyncio.wait_for(self.run(*args, **kwargs), timeout=timeout))
+        asyncio.run(
+            asyncio.wait_for(
+                self.run(
+                    transcription_config=transcription_config,
+                    stream=stream,
+                    channel_stream_pairs=channel_stream_pairs,
+                    audio_settings=audio_settings,
+                    from_cli=from_cli,
+                    extra_headers=extra_headers,
+                ),
+                timeout=timeout,
+            )
+        )
 
     async def send_message(self, message_type: str, data: Optional[Any] = None):
         """