The last official release of GS was v3.3.16 on Mar 3, 2020.
Many people had been requesting support for newer versions of PHP, which GS was lacking.
It has been my understanding that the main admin of the project had fallen ill, and was no longer able to dedicate the time to advance the project. And without any communication, or ability to post updates here, the CE version was born in an effort to keep the project alive and running.
Has the main branch stopped for good? I really couldnt answer that. But we are doing what we can to slowly contribute to the project, providing some modern updates and features.