Reloading dovecot after certificate renewal?

Is it enough to issue a service restart dovecot when a certificate renews or do I need to service stop/start?

-- "A thousand years ago we thought the world was a bowl. Five hundred years ago we knew it was a globe. Today we know it is flat and round carried through space on the back of a turtle. Don't you wonder what shape it will turn out to be tomorrow?" [Lord Vetinari]