Apple puts lots of effort into making it’s system safe and secure and requires all software running on macOS Catalina and higher to be notarized.
Notarization is a process of scanning and certification of software for not including malicious content. A common way to distribute malware is to take a popular app, infect it with malware and let users download it to their machines.
When user launches the application, macOS security system called Gatekeeper validates that the application has been previously notarized by verifying it’s scanning results.
With that said, new release of Xpiks (version 188.8.131.52 and higher) now is notarized so in case you couldn’t use it on Catalina, just go to downloads and download a fresh copy.
Now when opening a Xpiks, you will get a dialog that says “Apple checked it for malicious software and none was detected”.