Databases saved as *.pswx files are outdated and have not been recommended for several years now. Thus, the new Android app does not support this outdated file format anymore since version 12.1 and higher.
If you are using a *.pswx file on your smartphone you won't be able to open it with your mobile device since the last update to the current version.
However, in order to still have access to your data, please copy your *.pswx file to your computer. Now, open it with the Password Depot desktop program and save it as *.pswe format using the program menu Database -> Save. Transfer this database back to your smartphone and open it with the Android app.
PLEASE NOTE: If your *.pswx file is stored to the Protected Storage of the app, you will additionally need to also do another step in order to be able to transfer this database from the Protected Storage to your computer. Go to the app's Settings. If the app finds a *.pswx file in the Protected Storage, it will offer you to export this file. After the export you will need to convert your file with your computer again and then copy it to your smartphone in a last step.