Upgrade to V4 .kdbx file corrupts file

[tiborrr]

Describe the bug
Upgrading default keepass .kdbx file (v3.1) to (v4) causes the file not to be able to be opened in the official KeePass application.
Please find the following kdbx files as example:
problem_kdbx.zip

To Reproduce
Steps to reproduce the behaviour:

1. Open the no_problem.kdbx file
2. Click on
   
3. Save the file
4. Open the file in KeePass
   
   Expected behavior

The file should open

[betzburger]

And? Any comments on this? I used Authpass on my iPhone and saved the database. Now I can't open it with Keepass 2.5 on my company PC. I am not allowed to install Authpass on this PC. What should I do now?

[tiborrr]

I have been able to open it with keepassx. Then move all credentials in into a new database. I think I did this by exporting my data and then importing that into a new kdbx file, but do not know for sure. Then, save it and replace your corrupted file.

[betzburger]

Doesn't work for me. Also KeepassX can't open my file. Only AuthPass can open it. This incompatibility is bad. Luckily I have an older version of my file so I can use this and update it manually with all missing entries. No other way. Goodbye Authpass.