[throwaway314155]

> which presumably hasn't done a fresh pre-training over the web

What makes you think that?

> Did they figure out how to do more incremental knowledge updates somehow?

It's simple. You take the existing model and continue pretraining with newly collected data.

[Workaccount2]

A leak reported on by semi-analyses stated that they haven't pre-trained a new model since 4o due to compute constraints.