Our customer and we would like to have a "sharing feature parity" between the two session types "Professional Meeting and E2E". The customer does not see any security arguments in disabling this functionality in an E2E meeting as sharing of the whole screen content is allowed. The E2E session type should at least allow configuration.
It is totally incomprehensible for the end-user why this feature was not available in the E2EEv2 session types.
Currently “Share My Meeting Window” uses a non-video-based screen sharing protocol (MMP). Webex Room devices only support video-based screen sharing (H.264) that E2EEv2 now supports. Standard (non-E2EE) meetings a cloud-based transcoder is dynamically inserted into the meeting to convert the MMP to H.264 and vice versa so that we can interoperate between devices and Webex meeting clients. That means that the cloud-based transcoded needs access to the E2E Encrypted media. Therefore a transcoder cannot be added to an E2EE meeting as it would need to be able to decrypt the content that would break End-to-End Encryption. We cannot add the "Share My Meeting Window" feature to E2EEv2 at this time.
We plan to add "Share My Meeting Window" to support video-based screen sharing (H.264) and then we will easily be able to support E2EEv2 meetings. This will come as part of moving to a new back-end media platform that will start to roll out late Summer 2022.