GPT-5 deprecation December 2026: gpt-5, mini and o3 end 11 Dec, 30-day plan
OpenAI shuts six GPT-5 and o3 models on 11 December 2026. Its named GPT-5.6 replacements cost 2x to 8x more; GPT-6 models are often cheaper. Mapping, costs and a 30-day plan.