- Notification: the Gray Glacier upgrade is set for block 15,050,000, anticipated on June 29, 2022
- The Kiln Merge testnet, introduced earlier this year, will be decommissioned shortly after the Ethereum mainnet’s shift to proof-of-stake.
- Ropsten, Ethereum’s most enduring proof-of-work testnet, has transitioned to proof-of-stake. It will be disabled in Q4 2022.
- Rinkeby, a geth-based proof-of-authority testnet, will not move to proof-of-stake and will be discontinued in Q2/Q3 2023.
- Users and developers are urged to transition ASAP to Goerli or Sepolia to experiment with Ethereum in a post-merge scenario. After The Merge, Rinkeby will not be an appropriate testing ground for the Ethereum mainnet. Unplanned upgrades to the mainnet may no longer be applied to deprecated testnets.
Ethereum has numerous testnets for users and developers to conduct testing before engaging with the mainnet. These are effectively replicas of the Ethereum mainnet on which Ether and other tokens hold no value. They enable application, tooling, infrastructure, and protocol developers to implement modifications to their products (or the protocol itself!) in a low-stakes environment before advancing to the mainnet.
However, since testnets are fully functional blockchains, their history and state accumulate over time. This ultimately renders them more challenging to operate nodes on and to maintain. As a result, some testnets are periodically phased out. This occurred last year with the Pyrmont Beacon Chain testnet and more recently with the Kovan execution layer testnet.
With The Merge on the horizon, client developers have opted to deprecate additional testnets to concentrate their efforts on properly maintaining two of them in the long run: Goerli and Sepolia.
The Kiln, Rinkeby, and Ropsten testnets are now being phased out.
Testnet Deactivation Timeline
While these three testnets are now regarded as deprecated, users and developers still have time to arrange their migration prior to their complete shutdown. Kiln, Ropsten, and Rinkeby will be disabled according to the following timeline.
Kiln: Following Mainnet Merge
The Kiln testnet, launched in 2022 to offer a post-merge testing environment, will be terminated shortly after the Ethereum mainnet’s transition to proof-of-stake, projected for the latter half of 2022.
Developers should not utilize Kiln as a long-term testing platform. It is anticipated to be the initial testnet to be deactivated following The Merge on the Ethereum mainnet.
Ropsten: Q4 2022
The Ropsten testnet, which operated through The Merge on June 8, 2022, is slated for shutdown in Q4 2022.
Developers currently utilizing Ropsten as a staging/testing environment should transition to Goerli or Sepolia.
Rinkeby: Q2/Q3 2023
The Rinkeby testnet will not operate during The Merge. It is being substituted by Sepolia and will be shut down approximately one year after Sepolia has transitioned to proof-of-stake, around Q2/Q3 2023.
Once the Ethereum mainnet shifts to proof-of-stake, Rinkeby will no longer serve as an accurate staging environment for the mainnet. A compilation of changes introduced by The Merge that application developers should be cognizant of is accessible here. Again, be aware that these changes will not be applied to Rinkeby.
Developers currently utilizing Rinkeby as a staging/testing environment should prioritize transitioning to Goerli or Sepolia, and projects influenced by Ethereum’s move to proof-of-stake should aim to do so as quickly as possible.
Goerli & Sepolia
The two testnets that client developers will continue to support post-merge are Goerli and Sepolia.
The Goerli network will merge with the Prater Beacon Chain testnet. A new Beacon Chain has been established to facilitate Sepolia’s transition to proof-of-stake.
Goerli’s Beacon Chain will remain open for users wishing to operate a testnet validator. Sepolia will function with a permissioned validator set, akin to how some testnets operate today. Stakers aiming to test protocol upgrades before deployment to the mainnet should therefore utilize Goerli.
Goerli also boasts a robust community and a significant amount of existing infrastructure supporting it. Its state is the most similar to mainnet, which can be advantageous for testing smart contract interactions.
Sepolia, conversely, is relatively new, meaning its state and history are both quite limited. This results in the network being quick to synchronize with and that operating a node on it demands less storage. This is beneficial for users who wish to swiftly establish a node and engage directly with the network.
Recap
In summary, Kiln, Ropsten, and Rinkeby are now deprecated. While Kiln and Ropsten have already transitioned to proof-of-stake, Rinkeby will not undergo this upgrade.
Following The Merge on the mainnet, Kiln will be phased out. Subsequently, by the end of the year, Ropsten will also be disabled. Approximately one year after Sepolia’s transition to proof-of-stake, around Q2/Q3 2023, Rinkeby will be turned off.
Two testnets, Goerli and Sepolia, will continue to be maintained moving forward. Goerli is recommended for stakers to test protocol upgrades and developers who want to interact with a substantial existing state. Sepolia is suggested for users and developers who desire a lighter chain to sync with and engage.
To everyone who has assisted in running, maintaining, or supporting these networks, thank you!
Header image by Karl Hedin.
