For out field players, yes. But there's always been leeway with wicket-keepers. If the opposition captain allowed it, a team was allowed to replace their wicket keeper pre- the days of covid or concussions subs. It's just that they weren't allowed to bat (which they can do as a covid or concussion sub).
Five half-shouts in Dawson's first two overs, in the first session of the match, isn't great to see. Suggests that Harmer could have some fun later. (And given their need for wins, it would make sense if they've prepared something to suit Harmer.)
Great over from Potts to get rid of Mitchell. Been a few near misses with catches dissecting the keeper and slip