Apple recently released iPados 17.7.7 for older iPads, but users are now bumping into problems. This is going on.
iPados 17.7.7 causes serious problems: Apple retires update
Owners of recent iPads do not have to be afraid as long as you have installed the latest version of iPados: there are no problems with iPados 18. Only if you have an older iPad, can it be that some things are no longer quite good on your iPad.

The older iPads affected by the problems in iPados 17.7.7 include the iPad (6th generation) from 2018, the iPad Pro (10.5 inch) from 2017 and the iPad Pro 12.9 inch (2nd generation) from 2017. But every iPad that cannot update to iPados 18 has to be careful with this update.
Fortunately, it is no longer possible to update your iPad to this version of iPados. That’s because Apple has withdrawn the update. Apple herself has given no reason why they did this. But there are already several messages online from iPad owners with various problems.

For example, a user has problems with almost all apps for which you need an account. Every time they close and restart the app, they have to log in again with their account details.
Another user has problems with iPados 17.7.7 with some of his installed apps. Every time they open the apps, it looks like they are doing that for the first time. The apps therefore show the welcome message and the introduction text of the app every time.
It is not yet known when Apple will make the update available again. Probably updated version of iPados 17.7.7 will be available soon. But it is of course also possible that Apple will come up with a whole new update.