Vaults not recognized after system update

I made an Android System Update of my device and now none of my vaults are recognized by the game anymore. The save files (vault1.sav and vault2.sav) are still available in

/storage/sdcard1/0/Android/data/com.bethsoft.falloutshelter/files

However, the game does not want to load any of them.

Is there any way to force the game to load them? I bet not, but maybe someone else has some solution...