Unidentified developer problem on Mac

After installing v15.2.9, the following appeared when I tried to launch:

This has never happened before, and I had made no operating system changes or updates since previous downloads/installations of earlier Manager versions. Going to the Security preferences, I was able to bypass the restriction. Closing out and relaunching, I encountered no problem. But I wonder why, after using Manager for 1 ½ years, I see this. And I wonder if I’ll have to bypass security for every new version?

My OS is v10.10.3. The “identified developers” are those identified by Apple. Has something changed with NGSoftware?

Further problem:

I just installed v15.2.10. Upon launch, I got this:

I downloaded a fresh copy and installed it, but encountered the same problem.

Try the latest (15.2.11). Manager wasn’t digitally signed properly in previous 3 versions on Mac.

All is back to normal with v15.2.11. Thanks for the instant response.