Were you using PHP Mailer before updating do you know? That is now set in the amin admin settings of the store control panel so can you check what you have set there?
I have found that if you do something in store admin / main settings, you have to reenter your email password to get the email working again. I know I have had to do this several times on my sites to keep email working. Even if you enter the page I have had this happen. Might want to check it.