Post message to Teams Channel with Application Permission - documentation not correct?

Question

We have a need to post messages programmatically to Teams Channels and found the microsoft.graph.com API that should work for this. Unfortunately the GA release (v1.0) does not support Application Permissions and the only other way to Post a message seems to be to use the ROPC Auth flow, which is not allowed at my company.

After further research I found out that the documentation for the Beta release of this allows for using Application Permissions, which should work great for me. However, even though I added the "Teamwork.Migrate.All" permissions (Granting approved), I am still getting HTTP 401 Unauthorized.

I later found a second documentation page for the Beta release that does NOT specify Application Permissions as allowed for Posting a message in a Channel.

These are the two documentation pages with conflicting information: https://docs.microsoft.com/en-us/graph/api/channel-post-message?view=graph-rest-beta&tabs=http - Application Permission allowed https://docs.microsoft.com/en-us/graph/api/chatmessage-post?view=graph-rest-beta&tabs=http - Application Permission NOT allowed

Does someone know what is correct?

Also, is there currently any other way to post messages to Teams Channels programmatically?

Side note, the Bearer token I generate work fine for Getting Channel info, but not for Posting messages.

Answer 1

The first documentation is meant for "Create a new chatMessage in the specified channel", wherein the Second documentation is meant for "Create a new chatMessage in the specified channel or a chat". So there is a difference exists