The developers of Ethereum Classic announced a hard fork, the purpose of which will be to remove the so-called “difficulty bomb”.
The “difficulty bomb” is included in the original Ethereum Foundation documentation, and its purpose is to move to the Proof-of-Stake consensus algorithm. However, since Ethereum Classic does not plan to change the algorithm and remains on Proof-of-Work, this function is actually unnecessary for the project.
As stated in the early announcement of ETC Cooperative, since this fork represents an upgrade of the network, no separation of the block is expected, therefore, users should not wait for “free coins”.
This is a “small and positive” update since the “Difficulty Bomb” would quickly make PoW-mining not only unprofitable but, subsequently, impossible, as it was recently emphasized by the representative of ETCDEV team Darcy Reno.
In order to have a smooth transition and ensure the security of the network, one will need to upgrade to a minimum version getting 5.0.0 or parity 1.9.3 prior to block 5,900,000 which is currently estimated to occur on May 24, 2018.