Ethereum (ETH-USD) opens access to the "longer-lived public testnet," Kintsugi, to a wider public audience, according to a blog post. Note that testnets are networks used by protocol developers or smart contract developers to test protocol upgrades. Kintsugi is one of the last public testnets before the launch of Ether (ETH-USD) 2.0. After feedback has been included into the client software and the specifications, a final series of testnets will be launched. "Once these have upgraded and are stable, next up is Ethereum mainnet's transition to proof of stake" from proof of work, the post says. In the meantime, "we recommend most projects begin testing and prototyping on Kingtsugi to surface any potential issues soon." Ethereum (ETH-USD) gains more than 3% on Tuesday as it flirts with the key $4K level. Towards the end of November, ether continued outshining bitcoin.