The hardfork scheduled for Mon, 15 Aug 2016 14:00:00 GMT will include the following releases:
This effectively stops accounts with really low amounts of steem power from voting. Preventing spam of meaningless votes. This update was made with the intention of preventing bot attacks.
After the recent mining attack by a user named 'supercomputer' the steemit devs have been working hard to fix this bug. 'Supercomputer' did this attack by skipping the hashing part of mining and using ECDSA instead. The hacker could submit new blocks, using old blocks and changing their block-id. Then change his private key to sign the new block, effictively skipping the POW. @arhag will soon fully disclose how all of this took place.