GitHub removed Gemini 2.5 Pro and Gemini 3 Flash from every Copilot experience on Friday. The replacements are Gemini 3.1 Pro and Gemini 3.6 Flash.
The swap is not symmetrical
Gemini 2.5 Pro was a stable, generally available model. Its designated successor, Gemini 3.1 Pro, is labelled Preview. Teams that standardised on a stable model are being moved onto one carrying a preview label, which in GitHub's own taxonomy means it can change or disappear without the notice a GA model gets.
What 'no action required' actually covers
The changelog says no action is required, and for the removal that is accurate — nothing breaks, the models simply stop appearing. The same entry then notes that Copilot Enterprise administrators may need to enable access to the alternative models through their model policies. Those two sentences do not describe the same situation. In an organisation with a restrictive model policy, the old Gemini models vanish and the new ones are not automatically permitted, which leaves developers with no Gemini option at all until someone with admin rights notices.
The other change published the same day
GitHub also put enterprise-team model-policy targeting into public preview: an enterprise can set a baseline set of models and grant extra ones to individual teams, resolved least-restrictively. Most customers get the opt-in on 3 August, so the announcement precedes the availability. Buried in it is a consequence worth reading twice — once enterprise targeting is enabled, organisation-level model settings no longer apply. An org admin's existing restrictions are silently superseded by enterprise policy.
Why a changelog entry is worth reading
Model availability inside a coding tool is now a supply decision made by the tool vendor, not the developer. Which models a team can reach, and at what stability tier, is set two levels up — by the platform, then by an enterprise administrator — and it changes through changelog entries nobody is required to read.