8 months is not a problem, at least if the software isn't super complex and has a ton of bugs (both recently introduced and there since forever) and missing critical features (such as end to end encryption verification, the whole reason they exist). I'm sure it's a coincidence that no updates came out anymore after Zoom took over the team.
Anyway, without sarcasm, I don't use Keybase anymore but age isn't really the metric by which I define a dead app walking...
Based on their github issues and PRs, it looks like all they have to do to fix it is upgrade their version of react. The fact that they haven't done that yet is what tells me the app is dead.
Didnt they buy it to ick it up with some dirty form of surveillance capitalism?