GPT-5.5 GA for GitHub Copilot Same Day as Training-ON Default — OpenAI and GitHub Move in Lockstep

GitHub Blog·high signal

GitHub made GPT-5.5 generally available for Copilot on April 24 — the same day GitHub's training-ON default policy took effect. The timing means developers who don't opt out are now generating training data on OpenAI's strongest agentic model. Combined with GPT-5.5's Codex deployment at NVIDIA (10K engineers, debugging cycles from days to hours), this represents the fastest enterprise rollout of a new frontier model. For builders: GPT-5.5 delivers SOTA intelligence at half the cost of competing frontier coding models per Artificial Analysis.