It was revealed, during the latest Ethereum Core Developers Meeting #40, that two important improvements to the Ethereum network, Casper, and Sharder, will be delayed, but both might be introduced at the same time.
What is Casper?
Casper is a Proof-of-Stake (PoS) consensus model. This recent system, which was at first recommended in October 2017, is focused on getting rid of the existing weak points of Proof-of-Work (PoW) consensus systems in a Blockchain environment. Basically, it is going to make the network more cost-effective.
What is Sharding?
To put it simply, Sharding is a method of improving the number of transactions that the Ethereum Blockchain can cope with. The end game, with Sharding, is for each network node in the Blockchain to save only part of the entire chain, however, depend on other nodes to provide sufficient information. This will improve the scalability of the Ethereum network in the long run.
As pointed out above, these are two very significant updates that will massively change the entire ETH network. It is going to reduce miner block rewards down from 3 ETH per block to 0.6 ETH. According to Vitalik Buterin, the reason for rescheduling the update is that it is going to significantly decrease minimum ETH deposit amount that would be needed to take part in the ETH network.
Why is this needed?
It is necessary because the Ethereum network is quite young, but also popular. Especially due to the fact that it is the go-to platform for building decentralized applications.