Secret_key.txt's first line is too short! - After upgrade to 18.04


I made a upgrade from ubuntu 14.04 to 18.04 (A very loooong update).

Now it seems that all works well, but i see this info in the backup section

secret_key.txt’s first line is too short!

So i went to see this file and… It’s empty!!

How can i solve this trouble? I suppose that mail-in-a-box may generate a secure file for that.

From the code it looks like if you delete or move the secret_key.txt file from the backup/ folder, a new one will be generated when you run sudo mailinabox.

However, without the old secret you will not be able to read any previous backups.