What was retired
GitHub says it deprecated Gemini 3.7 Flash, GPT-5.5, GPT-5.4, GPT-5.4 mini, GPT-5 mini and Grok 4.5 across most Copilot experiences on October 19. Its suggested alternatives include Gemini 3.8 Flash, GPT-6.1 Sol, GPT-6 Luna and Grok 4.7, depending on the retired model.
GitHub advises updating workflows and integrations. Enterprise administrators may need to enable alternative models through policy; deprecated models do not require manual removal. Check the linked notice for the exact replacement mapping rather than guessing from similar names.
Source: GitHub: Copilot models deprecated on October 19, 2026 ↗
Find the assumptions you forgot
Our suggested migration check begins with a small inventory. Look at saved project instructions, team onboarding notes and any integration settings you actually maintain. A model name copied into an old tutorial can remain an assumption long after the visible selector changes.
Next, choose one ordinary task whose result you understand. In a fictional hobby app, that might be explaining a short function or proposing a test for an empty input. Keep the expected behavior independent of the model name.
Do not use one attractive answer as the migration verdict. Check whether the proposed change preserves behavior, follows the project’s conventions and passes the relevant tests. A replacement model being available is not the same as your project being ready to rely on it.
Leave a useful note for the next person
Record which model was selected, when you checked it and what task you used. If an administrator must change policy, route that request to the responsible person rather than treating a missing selector entry as an account failure.
Keep the note short enough to maintain. It should help someone repeat the check, not become another outdated model leaderboard. We have not tested the suggested alternatives against one another; this is a practical response to GitHub’s retirement notice, not a ranking of their capabilities.
Try this, then make it yours.
Find one model name in a project’s saved instructions. Check whether it is still supported, then attach one concrete task that would help validate a replacement.
Explore the tool ↗Follow the signal.
Our reporting starts here. Practical suggestions are our analysis, and vendor performance statements are claims unless independently verified. We haven’t hands-on tested this release.
