AI tool news: Opus 5.5, ChatGPT in Word, GPTs retire
Ten AI tool changes from 11 to 25 September 2026: Claude Opus 5.5 and higher limits, ChatGPT in Word, custom GPTs retiring, and which ones work in the UK.
Between 11 and 25 September, the AI assistants most people use changed in ways that matter more than any benchmark. Anthropic cut Claude's top-model price and raised usage limits. OpenAI quietly stopped ChatGPT switching into "thinking" mode for you, and announced that custom GPTs are on the way out. ChatGPT also arrived inside Microsoft Word, free.
This members' roundup covers ten tool-level changes from those two weeks. For each one: what changed, who gets it, whether it works in the UK, and a one-line verdict on whether you should care. Everything is dated and sourced to the company's own release notes or announcements.