Hello. I installed it two weeks ago. Problems with cities began. When submitting, the user entered the city incorrectly and this sometimes passed. The ad came out without a city. Today I updated it to 4.1.1 from the admin panel, now the city does not require it at all. The user may not specify it at all and it is published. What to do?

That is not bug or anything special, location was never required by default.
I think on 4.1.1 when user choose country, region and city are required (problem is that disabled select box cannot be required, this change after country selection).

I'm sorry, I found a problem. It was not in the update osclass

@Andrey
Would be nice to share your resolution so other people may find your exploration useful 

I haven't solved the problem yet. I rolled back the osclass to 3.9 directory and database and nothing changed. How to find a reason, I will definitely write

I was looking for a problem for a long time, the solution turned out to be simple. Copied the Beta theme to the archive, uninstalled and reinstalled. It all worked.

Please tell me how to fill in the geolocation fields of Cities automatically. For some reason, the base Russian Cities turned out to be in German (Fix a big mistake).
I purchased the OpenStreetMaps Plugin, but I understand that it cannot do this.  Thanks

I will check open street maps if it could fill also these coordinates.

Yes, please check.