I just upgraded from 6.0.10 to 7.1 and everything is working fine, except the "Send Later" feature. For example, if I schedule a message to be sent at 8am, it gets sent 7am.
The saved draft indicates the wrong time for sending too, in the "Scheduled send" field.
My timezone is (GMT -03:00 Brasilia). I also noticed that if I change it to Argentina (GMT -03:00) it works fine.
I checked timezone configs on my server and the command 'date' also returns the correct time.