@wojtek Edited messages could have an icon marking them that they were edited at some point. As for removal, I do have those entries in the database but I'm not loading them. If I would then we would need to came up with a way to present them. If you have any idea how we should present them, let me know. (even some sketch would be useful).

As for removed messages, I would display them as usual message, but instead of the text display simple placeholder:

(this message has been removed) (italic, light grey)

But should they be "mergeable"? I'm asking in context of message grouping:

IMHO they should be included in the layout just as they would be normally, but instead of the message text display placeholder text.

Regarding indicating - it could also have small (lower index) inscription next to the message "(edited)"

You already mentioned that:

It would be convenient to have some sort indication that the message was edited

I was thinking about adding ??️ or ✍️ or something like that with hover describing what it is.

It looks like everything is working OK after those changes.

works on receiving end on sender end it's being replaced by delivered icon (it flashes quickly)

@wojtek Well.. you have changed it, so you know what you have done, right?

Yes, I know at that point in time, but I may not recall it the next day, or in 1 year. Besides - you still try to update it... it just doesn't seem to work as expected.