# Release notes (/en/realtime-media/rtc-server-sdk/reference/release-notes/python)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

This document tracks important changes and improvements to the Server Gateway.

    ## v2.2.4 [#v224]

    Released on June 6, 2025.

    ### New features [#new-features-4]

    This release adds the following new features:

    #### Audio metadata support [#audio-metadata-support-1]

    This version adds the ability to send and receive audio metadata. In use-cases where you need to send auxiliary audio information, such as playback progress, call the `send_audio_metadata` method to transmit metadata. Remote users receive this information through the `on_audio_metadata_received` callback.

    #### Enhanced external video source support [#enhanced-external-video-source-support]

    This version adds the following fields to `ExternalVideoFrame`:

    * `fill_alpha_buffer` and `alpha_buffer` to support Alpha data channel.
    * `color_space` to support custom color space for externally captured video data.

    #### Secure data transmission [#secure-data-transmission]

    This version adds the `enable_encryption` method to support encryption when sending and receiving data streams. If you encounter problems during encryption and decryption that lead to failure, they are notified through the `on_encryption_error` callback.

    ## v2.1.0 [#v210]

    Released on December 11, 2024.

    This is the first version of the Server Gateway for Python.

    ### New features [#new-features-5]

    #### Media streams transmission [#media-streams-transmission]

    Server Gateway supports various audio and video encoding formats, such as H.264, H.265, VP8 for video, and OPUS, G722, and PCMA for audio. You can send and receive multiple types of audio and video data without being restricted by audio and video devices.

    #### Data streams transmission [#data-streams-transmission]

    Server Gateway supports sending and receiving data stream messages, applicable to use-cases requiring message transmission. For example, a chat application can use this feature to implement instant messaging between users.

    #### Multiple channels [#multiple-channels]

    Server Gateway supports sending or receiving media streams in multiple channels simultaneously, applicable to use-cases requiring multiple channel management. For example, an online education platform can conduct live classes for multiple classes simultaneously, ensuring that the audio and video data for each class does not interfere with one another.

    #### Subscribing to specific users [#subscribing-to-specific-users]

    You can selectively subscribe to specific users' media streams using their user IDs. For example, in a large conference, attendees can subscribe only to the speaker's media stream, saving bandwidth and improving efficiency.

    #### Audio mixing [#audio-mixing]

    Server Gateway supports mixing multiple audio streams, applicable to use-cases where multiple users or devices are sending streams simultaneously. For example, an online concert can mix audio streams from guitar, drums, and vocals into a high-quality audio stream for the audience.

    #### Cloud proxy [#cloud-proxy]

    Server Gateway allows access to Agora services within an intranet by whitelisting specific IPs and ports on the firewall. It is applicable to large enterprises, hospitals, universities, banks, and other institutions with high security requirements, ensuring a secure and stable connection.