Most stable version of spotify for offline songs?

[MrBrown3]

Hi guys, I've been traveling for almost a year and I use spotify to listen to my 3000+ songs that I've downloaded for offline usage.
There is a problem with this that occurred more then 5 times, and that is: the off line songs are all of the sudden not available anymore and the only fix is to reinstall the app and to download the songs all over again. Thus was the advice I got on the spotify forum.
This is not an easy task when you travel, especially if you live in a car without wifi. So the problem happened again today and I need to download my 3000 songs again in HQ. You can imagine this takes a lot of time and I don't want to be spending more days waisting to find good, free wifi when this problem happens again.
So I was wondering which version of spotify is the most stable one for off line use? I've heard that everything above version 8 is no good. I've installed version 7.9.0.746 because somebody advised me to on the spotify forum, but sadly this didn't help (lost all my songs).
*my cellphone (Oneplus 3T) is up to date, Spotify app is/was also up to date.

Any other advice is welcome.

Cheers