rather than allowing edits for invisible edits for X minutes, couldn’t your client just delay actually sending it for X minutes allowing to cancel or edit freely until that point?
Gmail allows a similar feature and it seems safer in a distributed system than relying on everyone else to respect what happens after you send a raw message and an edit right after
Isn’t the last version already that…well…last version?
If anything they could just leverage their work with proton that allows steam to play windows games on Linux to provide similar compatibility shims for old windows on modern windows