We have a new UI as experimental for now (chats without bubbles) and from my point of view, it would be good to make the default on the next version (5.4 or 6.0). We may consider dropping bubbles as well, as keeping them takes time if we want to add additional details to the UI. I would suggest keeping them for a version or two as a non-default feature, but no longer add new features to this old UI and add new features only to the new UI which would be enabled by default now.

Keeping bubbles (old UI) takes time not only to the fact that we need to add new features there, but we have to design a good UI, so we need to find a good place to display new icons or messages for a second time as most likely place used in new UI is not a good place for old UI.