The upgrade Constantipole was previously delayed owing to the major issues revealed by experts, right before the launch. The security vulnerabilities this upgrade was going to expose the network to were also critical because the blockchain had just suffered a fifty-one percent attack (51%).
The combinations of these two upgrades would now target the block seven million, two hundred and eighty thousandth block that would be put up for mining on the February 28th, 2019. Since the block would be presented for mining however the process is unpredictable therefore the exact dates may vary one to two day from the announced scheduled date.
The two different names represent two different upgrades that would be implemented on the same block of the Ethereum network. This would be one of the most important upgrades for the blockchain since Constantipole would be delaying the ICE AGE of the Ethereum blockchain.
The blockchain is about to move to Proof of Stake processing algorithm that would reduce the mining reward however the PoS is not ready to be implemented. The upgrade would ensure that the difficulty bomb feature of the blockchain that would stop miners from mining after the PoS switch would be delayed until the PoS ready to be implemented by the Ethereum foundation.
The second upgrade is basically a roll back for a previous update that would not actually be adding anything to the network but deleting previous additions for smoother operations on the blockchain.