Option to toggle between old UI/new UI

Please add option to toggle between old UI/new UI.

There are things I like, such as adding in timestamp for messages (I would actually prefer an option to see all times as hh:mm:ss if possible).

But, the reaction menu on hover is unnecessary, and I MUCH prefer the previous More (. . .) menu on messages. I think my biggest problem with it currently is it pops to the left instead of down.

The previous separation between messages was also good to have - I don't like it's been removed.