PSA: Timeline for Plan B SDP Deprecation and Removal - Please Migrate to Unified Plan

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Henrik Boström

Feb 10, 2021, 10:51:41 AMFeb 10
to discuss-webrtc

WebRTC 1.0 is now a W3C Recommendation (press release) with the standard SDP format, Unified Plan, being supported by all major browsers for a long time now.

It is important for a compatible and standardized web to remove non-standard APIs and Chromium's Plan B SDP is an example of this. The time has come to deprecate Plan B and prepare for its removal. This means that applications that have a dependency on Plan B has to migrate to the Unified Plan SDP before it is removed from Chromium-based browsers.

The target timeline that has been approved (intent thread) is:

  • M89 (Stable in February, 2021): Deprecation warning is added in the developer console.

  • M93 (Stable in August, 2021): Plan B is removed, with the option to extend this deadline by opting-in to a Reverse Origin Trial. More information about this option will be announced at a later date.

  • M96 (Stable in January, 2022): The extended deadline ends and Plan B is removed for everybody.

For more information, the "Unified Plan" Transition Guide that was written when Unified Plan's shipped back in M72 (January, 2019) is still very much applicable.

In M88 and M89 performance improvements significantly reduce the CPU usage and invocation time of WebRTC negotiation methods which greatly benefits Unified Plan usage. And more improvements are targeted for M90. If you encounter any issues migrating to Unified Plan, do let us know by filing an issue over at

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