Had a tag-team of problems with Office 365 Client updates and this one reared its ugly head just a I managed to successfully get the O365 updates syncing successfully.
Under Software Library|Office 365 Client Management|Office 365 Updates none of the client updates were checking in as ‘required’. Given that the O365 client on 5000-odd machines was at version 16.0.8201.2207 (v1705) this seemed odd to say the least. Everything was set correctly in SCCM for O365 Client Deployment so the summary screen should theoretically be showing that the whole estate needed at least every version beyond this.
After some considerable digging I discovered that for updates to work in SCCM, the CDNBaseUrl and the UpdateChannel settings in the registry MUST BE IDENTICAL. In my case, whoever had packaged the application had a bogus entry in the UpdateChannel setting that made no sense. I copied the CDNBaseURL setting (something along the lines of http://officecdn.microsoft.com/pr/492350f6-3a01-4f97-b9c0-c7c6ddf67d60) into the UpdateChannel setting, restarted the Microsoft Office Click-To-Run service and ran an update scan and update deployment policy refresh from the SCCM control panel applet. Immediately O365 client updates showed up as required. This can be checked under the following ConfigMgr report:
Compliance 8 – Computers in a specific compliance state for an update (secondary)
I then set up a GPO to push this URL out to the estate and watched the count increase.