Years after Twitter replaced the gun emoji with a green and orange water pistol, X has decided to replace it with a classic handgun. An X employee announced the change in a post last week.
Emojis are universal in that they share common designations across platforms (U+1F52B is the water pistol), which are decided by the Unicode Consortium. But it’s up to each platform owner to decide how they’re visually represented. That’s how we got the big cheeseburger emoji debacle that happened resolved in November 2017.
You’ll only see the weapon if you watch X on the web. At the time of writing, it doesn’t appear to have been updated in the mobile versions of the app, although it is apparently on the way at some point.