GitHub published the list of Copilot models being deprecated in August on 31 July.
Deprecation notices are the least-read item in any changelog and the one most likely to break something you own.
Why this one is worth reading
July added four models to Copilot from four different vendors. A month of additions makes it easy to assume the direction is only ever one way.
It is not. Models leave. A prompt tuned against a specific model, an evaluation baseline, a documented team standard — all of these have a shelf life set by someone else's roadmap.
What to do in the next two weeks
- Check which models your team actually uses, not which ones you enabled — usage and policy drift apart
- Re-run any prompt you have tuned against a deprecated model on its replacement before the cutover, not after
- Update internal documentation that names a specific model, or it will misdirect people for a year
The general lesson
Do not build a workflow that depends on one named model. The multi-vendor position Copilot reached in July is only useful if you can actually move between vendors when one of them retires something.