GitHub Copilot to Deprecate Several AI Models on Oct. 19, 2026

GitHub's Copilot service will retire a group of AI models on October 19, 2026, as announced in the GitHub Changelog on September 18, 2026. The deprecated models include Gemini 3.7 Flash, Gemini 3.8 Flash, GPT-5.5, GPT-5.6 Sol, GPT-5.4 mini, GPT-5 mini, GPT-5.6 Luna, and Grok 4.5/4.6. GitHub recommends switching to the listed alternative models, which are automatically enabled for Copilot Enterprise and Copilot Business customers under the default model enablement. Administrators who have disabled the global default can enable the alternatives manually via model policies in Copilot settings, after which the models appear in the Copilot Chat model selector. No action is required to remove the deprecated models; they will be unavailable after the deprecation date. GitHub advises customers to update any workflows or integrations that reference the retiring models before the cutoff.