Long-Term Support for Enterprise Stability

GitHub has announced a new long-term support (LTS) commitment for Copilot Business and Enterprise customers. Under this program, designated LTS models will remain available and supported for a full 12 months from their launch date, giving enterprises the stability required for internal security and safety reviews.

GPT-5.3-Codex: First LTS Model

GPT-5.3-Codex, developed in partnership with OpenAI, is GitHub's inaugural LTS model. Launched on February 5, 2026, it will remain available through February 4, 2027 for Copilot Business and Enterprise users. According to GitHub's data, GPT-5.3-Codex demonstrates a significantly high code survival rate among enterprise customers.

Rollout Timeline and Pricing

GPT-5.3-Codex will serve as the new default base model for Copilot, replacing GPT-4.1. The model carries a 1x premium request unit multiplier. GitHub will automatically enable GPT-5.3-Codex for all Copilot Business and Enterprise organizations within 60 days of this announcement, with the model becoming the mandatory base model by May 17, 2026.

Key dates:

• March 18, 2026: LTS program and base model changes announced
• May 17, 2026: GPT-5.3-Codex becomes the base model for all Copilot Business and Enterprise organizations
• February 4, 2027: End of LTS availability window

Scope and Migration Path

These changes apply exclusively to Copilot Business and Copilot Enterprise plans. Individual plans (Copilot Pro, Pro+, and Free) will continue to follow standard model deprecation timelines. Organizations requiring additional time to migrate can contact their account team for support. Documentation on supported models and model management policies is available in GitHub's official docs.