Ether (ETH or Ξ) is the native cryptocurrency used on the Ethereum network and is used to compensate miners who secure transactions. A planned upgrade to the Ethereum protocol in 2019-2021 would replace mining with a less computationally expensive Proof of Stake mechanism which will be secured by validators, who are also expected to receive a proportional compensation in Ether. Ether also has many current use cases, such as a store of value (e.g. in lending collateral), a medium of exchange (e.g. in trade and payments), and a unit of account (e.g. in digital marketplaces).