The first network upgrade of Zcash will be done through a hard fork at the block number 347500[7] which is expected to be on 25 June 2018. A new feature will be introduced that allows users to set transaction expiration times.[8] Five Zcash Improvement Proposals namely, 143, 200, 201, 203 will be implemented[9]. This upgrade also improved the signature verification that helps improve the transaction speed.
Lol. You are too late reporting this network upgrade because its already July. You should have reported that they have successful done it.
Zcash Successfully Activates Overwinter, the First ZEC Hard Fork
Zcash Activates Overwinter Hard Fork
The network upgrade went live at block 347,500, which was mined on Tuesday, June 26, at approximately 1:37 UTC.
As CCN reported, Overwinter introduces several performance enhancements to the Zcash protocol. One such upgrade is “transaction expiry,” which allows the mempool to automatically cancel ZEC transactions that have not been added to a block within a predetermined period of 20 blocks (~50 minutes).
Perhaps more notable, however, are the features that will prepare the network for future hard forks, including the highly-anticipated Sapling upgrade, which is scheduled to go live in October. Developers say that this fork will increase transaction efficiency and scalability, particularly for transactions made from privacy-enhancing “shielded addresses.”
https://www.ccn.com/zcash-successfully-activates-overwinter-the-first-zec-hard-fork/As per the article, there's a lot included in the upgrade, including replay protection.
