qregex now ignores empty envelope senders. With previous versions, it was possible to write regular expressions that would match the empty envelope sender and thus inadvertently block bounce messages. This is no longer the case. It was also pointed out to me that some of the example REs in the qregex documentation don’t actually work. I’ve replaced these with new REs that do work. Thanks to Thanos and Alex for bringing this to my attention. My qregex-starttls-2way-auth.patch includes this new version of qregex as well.