I’ve always found the use of the *.5 naming kinda silly when it became a thing. When OpenAI released 3.5, they said they already had 4 underway at the time, they were just tweaking 3 be better for ChatGPT. It felt like a scrappy startup name, and now it’s spread across the industry. Anthropic naming their models Sonnet 3, 3.5, 3.5 (new), 3.7 felt like the worst offender of this naming scheme.
I’m a much bigger fan of semver (not skipping to .5 though), date based (“Gemini Pro 2025”), or number + meaningful letter (eg 4o - “Omni”) for model names.