I used the new osmand~ version and when starting a routing I got a message like “could not use data, it is too old”. I forgot to make a screenshot and just downloaded the new maps. Maybe someone could try to reproduce it.
If no routing is availabe when the map data is stale I see a big problem. Getting a list with new map data would lead to an unusable offline routing until all needed maps are downloaded.
Again: I am unsure about that error message.
So you update the app but not the map? Why? 
How old is your map data? Mine is a couple of months old and it works.
Maybe related to this Routing declaring maps 'outdated or missing' when they are only 2-3 months old, and then they are not used even when 'use downloaded maps' is selected · Issue #22178 · osmandapp/OsmAnd · GitHub
use A 2phase map routing method.
F-Droid does unattented updates, Osmand~ doesn’t update the maps at the same moment.
Maybe it could be a switchable feature in F-Droid: If the package got updated it should be run once with the option --update-only-and-end or similar.
Maps might be huge, it’s up to the user to update them when they use a free Wi-Fi
It would be even nicer, if the user would have the option to configure auto updates of app data after app update. Using free Wi-Fi only for maps updates could be an configurable option, too.
Back to the original problem: if a new version of an App requires large downloads of data to work again the users should be warned before they update the App because once they did update there is often no way back and redownloading eg Osmand maps can be easily 10s of Gigabytes.
How many countries do you need?
Always more than fit into the memory of my phone 
@RichZ No micro SD card? I would not buy a phone without a micro SD card slot.
@Licaon_Kter 6GB for germany is too much to be updated within a minute, at least to me.
That would be a nice feature. Additionaly the F-Droid devs would need to know that the problem exists for a special version and set the flag. If we are lucky a beta tester reports such a fact in a bug report.
I completely agree. I downloaded just for my county and it was almost .06 - .07GB in size. The whole country was approx 18-22GB. Lols.