Molly, a fork of Signal, has not been updated for three months. As of now, its latest release was on 31 July, version v8.19.2-4.
It contains vulnerabilities that had been simply fixed in mainline Signal. Take for example the latest exploit disclosed in October; it has been fixed in Signal 8.27. Meanwhile Molly remains vulnerable.
It is currently recommended to use mainline Signal and delete Molly until they at least return to updating their app adequately, if they ever will.
Source: Hacker News · Summarized by HeadlinesBriefing