Stumbled across the next bug (!?!). After everything seemed to work wit the latest 7.1.1 Update things went tits up again. Switching to mobile data was OK for the last days. Now we are in the Netherlands for a few days. At first everything worked fine as well. But since yesterday afternoon mobile data fails to connect in total. Even rebooting doesn't help.
after the latest update my navigation system can not find any GPS signals. I testet everything (reboot, flight mode, battery save, ...) but nothings helps.
I have an Umidigi Z.
Thanks for help!
Just as a addition: Data roaming isn't working for me (and I mean it doesn't work at all!). As soon as I was back in Germany everything was working well again!