Dear developer (Christian),
do you know, where the backup button is?
Please check my screenshot.
Restore…yes, but I miss the button 
(v.2.6.7)
We will replace this function in the future with the server login.
Well, there´s no chance to backup the database on my phone?
We don’t provide this feature anymore, because it occurs to issue. We will focus on a goog server sync only.