When the 3.4.0 release was published, users found a few issues where Xdebug would crash when it was deciding whether any feature needed to be activated through a trigger. In December, I spend a lot of time tracking this down, and made several attempts at a fix. Xdebug did not correctly dereference this special internal PHP variable information. Over the holiday period, several users tested out this fix and confirmed that it indeed worked. I didn't manage to release Xdebug 3.4.1 before the year was over, but will come early in January.