The TL;DR I got from this article:
* Fees will go up for card not present transactions (online and phone) and fall a bit for card present transactions.
* Overall, Visa is increasing fees to make more money than before since there aren’t any other details provided.
My take is that if Mastercard plays it right, this is a good time to capture a higher market share at Visa’s expense (though it wouldn’t come anywhere close to toppling Visa’s lead).