The two network upgrades, Constantinople and St. Petersburg, apparently went live on the Ethereum blockchain on Feb. 28, according to network monitoring site ethstats.net.
As planned, the network update went live on the main Ethereum network at block 7,280,000, which was mined at 19:52 (UTC) on Feb. 28. Not everyone has adopted the new update though, with only 29.8% of Geth and Parity clients running the Constantinople version according to Ethernodes.org.
The Constantinople network upgrade comes with several efficiency improvements for the Ethereum network, such as reduced transaction fees for some operations on the network. The fork was planned to occur on block number 7,080,000, but was delayed due to a vulnerability issue found in it by ChainSecurity on Jan. 15.
The St. Petersburg update is meant to disable a part of the Constantinople code, specifically Ethereum Improvement Proposal (EIP) 1283, which was identified to have the security vulnerability. Four different EIPs have been activated on the Ethereum network with the release of the Constantinople and St. Petersberg updates.
Before a network update, Ethereum clients such as Geth and Parity upgrade their software to include the new changes to the protocol, but none of the new features are activated before a pre-defined block is mined. Once that specific block has been mined, everyone starts using the new features at the same time.
As of press time, no major gains or losses were detected to the price of Ethereum in response to the network update, with Ethereum trading at $138.19 as of the time of writing.