Named after the capital of the Byzantine Empire, Constantinople forms part of a three-part system wide upgrade (known as a hard fork) of the Ethereum network called Metropolis and is estimated to take place between the 14th -16th of January. It combines a total of five ethereum improvement proposals (EIPs), and while the majority are non-controversial tweaks, one aspect of the upgrade has been the cause of some controversy.
In particular, Constantinople delays the “difficulty bomb” an algorithm in ethereum’s network that increases mining difficulty over time. Because the upgrade will decrease the mining difficulty, it also takes steps to reduce the reward miners are given for securing the network – down from 3 ETH to 2 ETH per block. This has led miners to express discontent with the upgrade. But at the same time, major mining pools have stepped up in support of the change.
Splits aside, there are also other risks to a system-wide network upgrade as well including Code bugs that can cause networks to splinter, and algorithms can go awry, leading to unanticipated difficulties. However developers are confident that such risks are minimal in the Constantinople hard fork with months of testing seeking to sought out any software vulnerabilities in the lead up to this week's major event.
An important thing to take note of is that Ethereum’s Constantinople hard fork is expected to be non-contentious, meaning that everyone will be in agreement to take the Ethereum blockchain on its new path.
Unlike Bitcoin Cash’s hard fork back in November 2018, where a war between the 2 chains harmed the entire crypto ecosystem, Ethereum’s fork is expected to be a peaceful transition, as if nothing happened. ETH holders do not need to prepare for this update and can just ride it out.
However, if you do wish to participate in Ethereum’s hard fork, all exchanges are urging holders of ETH to allow sufficient time for deposits to be processed before the fork, and some exchanges will even halt ETH deposits prior to the fork.