Given a client assigned to the semi-annual channel for O365 in the period when two versions of O365 are supported in that channel... For instance, currently v2008 and v2102 are both supported versions of O365 semi-annual channel. For clients in the newly named state Semi-Annual Channel Extended (for example running v2008 at this time) the CDN is not accessible for installing new components like Visio or Project. Looking in the registry, the client is assigned to an "AudienceID" of 89815e81-c82e-49a3-99dc-2b99229cf632 and Audience Data of "Production::DCEXT" I assume this means "Deferred Channel Extended." It doesnt appear that setup.exe knows how to cope with this classification. When attempting to install Visio on a client in this state, the installation fails with the error code 30183-2016 (400). Looking through the log file for the office install, it looks like the setup program is unable to determine the proper CDN channel to use and so applies a channel override of "Monthly"
The client is unable to download the semi-annual channel version of the CABs from the Monthly CDN channel and so it errors.
I am not positive how setup.exe determines the channel of the software installed - the channel identifiers are correct in the "Update Channel" and "CDNBaseURL" at 7ffbc etc. The only thing that seems off are those AudienceID and AudienceData values.
The client can be brought into functioning by updating the client from the Semi-Annual Extended Channel version (currently v2008) to the Semi-Annual Channel version (currently v2102) --- but BOTH versions should be in full support by Microsoft. It is not a great user experience for the setup application to break for a few months twice a year during the transition period when two version of Office are supported in the semi-annual channel.



