For detailed notes on the recent Dev Call from a few days ago, Cryptomines posted a very detailed summary of the call, and in particular details regarding the hardfork, difficulty bomb etc.. I had linked to it that day, but it wouldn't get much visibility as I'm relatively new here. So here ya go.
https://www.reddit.com/r/EtherMining/comments/6t56a0/important_information_from_todays_ethereum_dev/
RE: Ethereum: First Metropolis Upgrade in late September