In previous versions of Slack, when I pressed the up arrow, it "pasted" the last message I sent into the message field, so I can repeat the message. If I kept pressing the up arrow, it did the same with previous sent messages.
Now, with the new version, when I press up arrow, it edits the last message. The funny thing is that, searching in Google, in some posts of shortcuts in Slack, it explains that pressing up arrow you edit the last message and the posts are from old versions. Why did I have this functionality of repeating previous message and now I don't have it?
Best Answer
There used to be an option (I think in the advanced tab of preferences) that, when checked, allowed the up button to cycle through previous messages and Cmd + up to edit your previous message. The default was to edit the last message (like the current functionality), but by checking the box you could get the functionality that you and I are both missing dearly.
They removed it very recently (in the last couple of weeks). I'm not sure why, I was searching trying to figure out why when I came across your post.
Update: found this on reddit :(