I just updated my QNAP 251 to firmware
NOW Asset 7.4 does not work properly. It cannot get opened in the AppCenter any more, the configuration side does not open as usual in the browser, just a spinner who never stops.

That's just one thing. What changed using Asset is the behaviour on Albums with multiple CDs. I always told Asset to handle these Albums as ONE CD, so there was only one cover visable. Now a Double-CD has two times the cover, an album with 3 CDs has three times the cover and so on. The option is still checked in the configuration ! BTW the CDs are then tagged with CD 1 of 2 / 2 of 2 and so on.
This worked fine for years now, but it doesn't work any more without making any changes.

Any idea ?

Can I easily go back to 7.3 ? All the problems began with the update to 7.4 .....