That's because models have training cut-off dates. It's important to take those into account when working with them: https://simonwillison.net/2025/Mar/11/using-llms-for-code/#a...
I've switched to o4-mini-high via ChatGPT as my default model for a lot of code because it can use its search function to lookup the latest documentation.
You can tell it "look up the most recent version of library X and use that" and it will often work!
I even used it for a frustrating upgrade recently - I pasted in some previous code and prompted this:
This code needs to be upgraded to the new recommended JavaScript library from Google. Figure out what that is and then look up enough documentation to port this code to it.
It did exactly what I asked: https://simonwillison.net/2025/Apr/21/ai-assisted-search/#la...