It seems that the last time IABot has worked for real in Ukrainian Wikipedia was in 2019. The contributions for 2020 and 2021 almost fit within one screen height:
https://uk.wikipedia.org/wiki/Спеціальна:Внесок/InternetArchiveBot
Is there any problem/exception that is happening for ukwiki that needs to be resolved?
I see T288495 is related to ukwiki, but it is not clear what severity of that task is.
I have now discovered that IABot has management interface, and on it ukwiki is currently disabled with the link to the aforementioned task: https://iabot.toolforge.org/index.php?page=runpages
Unfortunately the task description is not detailed enough for someone not already familiar with IABot to figure out what exactly is the problem and how it should be fixed (i.e. if something in the bot's codebase needs to be fixed vs something in the management panel has to be tweaked vs some preparatory changes in ukwiki itself have to be done vs something else).
Also while it seems that it is now clear why the bot is stopped now, it is not clear why it almost didn't run for the last 2 years.
It seems IAB stopped 5 days ago at all. See [https://zh.wikipedia.org/wiki/Special:%E7%94%A8%E6%88%B7%E8%B4%A1%E7%8C%AE/InternetArchiveBot], [https://en.wikipedia.org/wiki/Special:Contributions/InternetArchiveBot].