SpamSieve not working after update to 13.3.1

I was using SpamSieve on 13.2 and it was working fine until I updated to 13.3.1 yesterday and now I always get this message:

SCR-20230415-grzu 496x478

I tried re-downloading a bunch of times, but it’s always the same result.
I uninstalled, restarted and tried reinstalling.
Any ideas?

It sounds like there’s something wrong with the certificates on your Mac such that it erroneously thinks that SpamSieve is damaged. You can work around this as described under If macOS Won’t Launch the App.

That was it, thank you!
I’m still trying the app and was kinda afraid when that happened after an update, glad it wasn’t the app itself.
I’m gonna try to find out what’s up with my certificates that the download broke the app.