The first key announcement about a nontrivial dependency upgrade project should be made in the https://discuss.openedx.org/c/announcements/maintainers/45 forum with an appropriate, obvious title (such as “Django 4.2 Upgrade”). Some teams (such as Arbi-BOM and FED-BOM at 2U) may have other Slack channels, email lists, etc. that they routinely send announcements to. The orchestration team is only responsible for the main forum post and any other communication channels they normally use for announcements; if other organizations wish to repeat the announcement in their internal communication channels, they are free to do so.
Later announcements should be made as replies to the original Maintainers forum post, not as new topics. The orchestration team is again free to repeat in any other communication channels they routinely use for announcements, and other organizations are again free to repeat in their internal communication channels if desired.
Announcement of the instructions for performing the upgrade in a given repository, and a request for repository maintainers to pick an appropriate service level for each impacted repository for which they are responsible.
Any changes to the project documentation that may significantly impact how teams can / must perform the upgrade.
Announcement of successful completion of the upgrade!
There may also be other announcements if more help is needed, there’s a change in orchestration team, or something else significant changes about the status of the project. And there may be questions or suggestions in the forum topic from people outside the orchestration team, along with related discussion. But most discussion of smaller changes like completion of the upgrade in a particular service should be limited to the appropriate repository-specific GitHub issue or other communication channel with an appropriately-scoped audience.