• The blobs are coming: Dencun will go live on Goerli at 6:32 UTC on January 17, 2024.
• Dencun will be Goerli’s last upgrade before core teams stop supporting it. More on this in a previous post.
• Assuming the Goerli upgrade goes well, the Sepolia and Holesky testnets will activate Dencun over the next few weeks.
• To receive an email alert for network upgrade announcements, subscribe here.

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The Dencun network upgrade is scheduled to activate on the Goerli testnet at 6:32 UTC on January 17, 2024. The upgrade includes several changes, most notably the introduction of ephemeral data blobs with EIP-4844, also known as “protodanksharding”, which will help reduce L2 transaction fees.

Dencun follows last year’s Shapella upgrade. It will first be deployed to the Goerli testnet. Then, if no major issues are found, to Sepolia and Holesky. Once Dencun is running smoothly on all three testnets, mainnet activation will be scheduled.

Dencun will be Goerli’s last upgrade. After it has been activated on mainnet, client and EF testing teams will stop supporting the Goerli testnet. For more details, see this previous announcement.

Upgrade Specification

The Dencun upgrade combines changes to both Ethereum’s consensus and execution layers. The full list of protocol changes can be found in EIP-7569. For reference, they are:

Deneb

Complete python specifications for changes affecting Ethereum’s consensus layer can be found in the deneb folder of the ethereum/consensus-specs repository.

Cancun

The EIPs linked above contain the full specifications for changes affecting Ethereum’s execution layer.

Additionally, a python specification for these is being implemented in the ethereum/execution-specs repository.

Lastly, Deneb requires changes to the Engine API, used for communication between the consensus and execution layer nodes. These are specified in the cancun.md file of the ethereum/execution-apis repository.

Client Releases

The following client releases support Dencun on Goerli. Further versions will activate support on other testnets and mainnet. Once these are released, another announcement will be made here.

When choosing which client to run, validators should be especially mindful of the risks of running a majority client on either the execution layer (EL) or consensus layer (CL). An explainer of these risks and their consequences can be found here. An estimate of current EL and CL client distribution and guides for switching from one client to another can be found here.

Consensus Layer Goerli Releases

Note: when running a validator, both the Consensus Layer Beacon Node and Validator Client must be updated.

Execution Layer Goerli Releases

Note: while Reth supports Dencun, the client is still pending a full audit and is not recommended for production use. See the Reth README for more context.

Dencun Bug Bounty Bonus

All Dencun-related bug bounties for in-scope vulnerabilities will receive a 2x multiplier between now and two weeks prior to when the mainnet upgrade is scheduled to take place. Critical bugs are now worth up to $500,000 USD! See the bug bounty program for more details.

FAQ

As an Ethereum user or Ether holder, is there anything I need to do?

In short, no.

If you use an exchange, digital wallet or hardware wallet you do not need to do anything unless you are informed to take additional steps by your exchange or wallet provider.

If you run your own Ethereum node, see the next question.

As a non-staking Goerli node operator, what do I need to do?

To be compatible with the Goerli upgrade, update your node to the version of your Ethereum client listed in the table above.

As a Goerli staker, what do I need to do?

To be compatible with the Goerli upgrade, update your node to the version of your Ethereum client listed in the table above. Make sure both your beacon node and validator client are updated!

As a non-Goerli node operator or staker, what do I need to do?

Nothing for now. Further announcements will be made for Dencun’s activation on Sepolia, Holesky and mainnet. You can sign up to receive an email alert for them here.

Stakers who want to run through the upgrade process more times before mainnet are encouraged to use ephemery.dev, which will soon support Dencun.

What happens if I am a Goerli staker or node operator and I do not participate in the upgrade?

If you are using an Ethereum client that is not updated to the latest version (listed above), your client will sync to the pre-fork blockchain once the upgrade occurs.

You will be stuck on an incompatible chain following the old rules and will be unable to send Ether or operate on the post-Dencun Ethereum network.

As an application or tooling developer, what should I do?

Review the EIPs included in Dencun to determine if and how they affect your project — there are many new exciting features being introduced across both the execution and consensus layers! The only EIPs with backwards compatibility implications are EIP-6780, EIP-7044 and EIP-7514.

Where can I follow the upgrade happening?

The Goerli upgrade will be livestreamed here.

Why “Dencun”?

Upgrades to the consensus layer use star names, and those to the execution layer follow Devcon city names. “Dencun” is the combination of Deneb, a first-magnitude star in the Cygnus constellation, and Cancun, the location for Devcon 3.

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Original cover image by Darren Lawrence, with modifications by Tomo Saito.

Important update: since the initial publication of this post, Lodestar has published a new release, v1.15.0, which Holesky users must upgrade to prior to Dencun’s activation on February 7th. Additionally, Prysm and Nimbus have both published highly recommended releases for Holesky. Prysm users are encouraged to use v4.2.1, and Nimbus users v24.2.0.

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• Goerli blobs are here: Dencun went live on Goerli at 6:32 UTC on January 17, 2024. You can now use blobs there!
• Sepolia and Holesky will upgrade over the next two weeks. Dencun will activate on Sepolia at epoch 132608 (January 30th, 22:51 UTC), and on Holesky at epoch 29696 (February 7th, 11:35 UTC).
• Client releases in this announcement are suitable for both testnet upgrades.
• Assuming the Sepolia and Holesky upgrades go well, Dencun will be scheduled on the Ethereum mainnet next.
• To receive an email alert for network upgrade announcements, including the Dencun mainnet one, subscribe here.

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The Dencun network upgrade has successfully activated on the Goerli testnet on January 17, 2024. It is now scheduled for the two remaining testnets, Sepolia and Holesky, at the following times:

The upgrade includes several changes, most notably the introduction of ephemeral data blobs with EIP-4844, also known as “protodanksharding”, which will help reduce L2 transaction fees.

Dencun follows last year’s Shapella upgrade. It will first be deployed to Ethereum testnets. Once these all are smoothly running the upgrade, Dencun will be scheduled for deployment on the Ethereum mainnet.

Upgrade Specification

The Dencun upgrade combines changes to both Ethereum’s consensus and execution layers. The full list of protocol changes can be found in EIP-7569. For reference, they are:

Deneb

Complete python specifications for changes affecting Ethereum’s consensus layer can be found in the deneb folder of the ethereum/consensus-specs repository.

Cancun

The EIPs linked above contain the full specifications for changes affecting Ethereum’s execution layer.

Additionally, a python specification for these is being implemented in the ethereum/execution-specs repository.

Lastly, Deneb requires changes to the Engine API, used for communication between the consensus and execution layer nodes. These are specified in the cancun.md file of the ethereum/execution-apis repository.

Client Releases

The following client releases support Dencun on both Sepolia and Holesky. Further versions will activate support on mainnet. Once these are released, another announcement will be made on this blog.

When choosing which client to run, validators should be especially mindful of the risks of running a majority client on either the execution layer (EL) or consensus layer (CL). An explainer of these risks and their consequences can be found here. An estimate of current EL and CL client distribution and guides for switching from one client to another can be found here.

Consensus Layer Sepolia & Holesky Releases

Notes:

• Holesky Lodestar v1.15.0-rc.0 users must upgrade to v1.15.0.
• Holesky Nimbus v24.1.2 users are highly encouraged to upgrade to v24.2.0.
• Holesky Prysm v4.2.1-rc.1 users are highly encouraged to upgrade to v4.2.1.
• When running a validator, both the Consensus Layer Beacon Node and Validator Client must be updated.

Execution Layer Sepolia & Holesky Releases

Note: while Reth supports Dencun, the client is still pending a full audit and is not recommended for production use. See the Reth README for more context.

FAQ

As an Ethereum user or Ether holder, is there anything I need to do?

In short, no.

If you use an exchange, digital wallet or hardware wallet you do not need to do anything unless you are informed to take additional steps by your exchange or wallet provider.

If you run your own Ethereum node, see the next question.

As a non-staking Sepolia or Holesky node operator, what do I need to do?

To be compatible with the upgrade on either testnet, update your node’s execution and consensus layer clients to the versions listed in the table above.

As a Sepolia or Holesky staker, what do I need to do?

To be compatible with the upgrade on either testnet, update your node’s execution and consensus layer clients to the versions listed in the table above. Make sure both your beacon node and validator client are updated.

As a non-Sepolia or Holesky node operator or staker, what do I need to do?

Nothing for now. Further announcements will be made for Dencun’s activation on mainnet. You can sign up to receive an email alert for them here.

Stakers who want to run through the upgrade process more times before mainnet are encouraged to use ephemery.dev, which now supports Dencun.

What happens if I am a Sepolia or Holesky staker or node operator and I do not participate in the upgrade?

If you are using an Ethereum client that is not updated to the latest version (listed above), your client will sync to the pre-fork blockchain once the upgrade occurs.

You will be stuck on an incompatible chain following the old rules and will be unable to send Ether or operate on the post-Dencun Ethereum network.

As an application or tooling developer, what should I do?

Review the EIPs included in Dencun to determine if and how they affect your project — there are many new exciting features being introduced across both the execution and consensus layers! The only EIPs with backwards compatibility implications are EIP-6780, EIP-7044 and EIP-7514.

Why “Dencun”?

Upgrades to the consensus layer use star names, and those to the execution layer follow Devcon city names. “Dencun” is the combination of Deneb, a first-magnitude star in the Cygnus constellation, and Cancun, the location for Devcon 3.

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Original cover image by Darren Lawrence, with modifications by Tomo Saito.

March 12, 2024 update: Since the initial publication of this post, several client teams have made Dencun-compatible releases containing significant performance and stability improvements. While previously announced versions are still considered sufficient for the upgrade, a column has been added to the Client Releases tables highlighting the latest recommended versions for all clients.

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• Mainnet blobs are coming .oO: Two years after its ETHDenver inception, dozens of testing calls and devnets later, protodanksharding is finally going live on mainnet!
• Dencun will activate on the Ethereum mainnet at epoch 269568, occurring on March 13, 2024 at 13:55 UTC. Node operators & stakers must upgrade their software to releases listed in this announcement.
• To receive email alerts for future network upgrade announcements, subscribe here.

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The Dencun network upgrade has successfully activated on all testnets. It is now set for deployment on the Ethereum mainnet and will activate on the network at epoch 269568, occurring on March 13, 2024 at 13:55 UTC.

The upgrade, which follows last year’s Shapella upgrade, includes several changes, most notably the introduction of ephemeral data blobs with EIP-4844, also known as “protodanksharding”, which will help reduce L2 transaction fees.

If you’d like to follow the upgrade as it happens, please join the community livestream.

Upgrade Specification

The Dencun upgrade combines changes to both Ethereum’s consensus and execution layers. The full list of protocol changes can be found in EIP-7569. For reference, they are:

Deneb

Complete python specifications for changes affecting Ethereum’s consensus layer can be found in the deneb folder of the ethereum/consensus-specs repository.

Cancun

The EIPs linked above contain the full specifications for changes affecting Ethereum’s execution layer.

Additionally, a python specification for these is being implemented in the ethereum/execution-specs repository.

Lastly, Deneb requires changes to the Engine API, used for communication between the consensus and execution layer nodes. These are specified in the cancun.md file of the ethereum/execution-apis repository.

Client Releases

When choosing which client to run, validators should be especially mindful of the risks of running a majority client on either the execution layer (EL) or consensus layer (CL). An explainer of these risks and their consequences can be found here. An estimate of current EL and CL client distribution and guides for switching from one client to another can be found here.

Consensus Layer Mainnet Releases

Note: when running a validator, both the Consensus Layer Beacon Node and Validator Client must be updated.

Execution Layer Mainnet Releases

Notes:

• While Reth supports Dencun, the client is undergoing a full audit and may not be suitable for all production use cases. See the Reth README for more context.

FAQ

As an Ethereum user or Ether holder, is there anything I need to do?

In short, no. You can join us on the livestream to watch it all happen live!

If you use an exchange, digital wallet or hardware wallet you do not need to do anything unless you are informed to take additional steps by your exchange or wallet provider.

If you run your own Ethereum node, see the next question.

As a non-staking node operator, what do I need to do?

To be compatible with the mainnet Dencun upgrade, update your node’s execution and consensus layer clients to the versions listed in the table above.

As a staker, what do I need to do?

To be compatible with the mainnet Dencun upgrade, update your node’s execution and consensus layer clients to the versions listed in the table above. Make sure both your beacon node and validator client are updated, as well as any external dependencies, such as external block building software.

Additionally, stakers who want to run through the upgrade process more times before mainnet are encouraged to use ephemery.dev, which now supports Dencun.

What happens if I am a staker or node operator and I do not participate in the upgrade?

If you are using an Ethereum client that is not updated to the latest version (listed above), your client will sync to the pre-fork blockchain once the upgrade occurs.

You will be stuck on an incompatible chain following the old rules and will be unable to send Ether or operate on the post-Dencun Ethereum network.

As an application or tooling developer, what should I do?

Review the EIPs included in Dencun to determine if and how they affect your project — there are many new exciting features being introduced across both the execution and consensus layers! The only EIPs with backwards compatibility implications are EIP-6780, EIP-7044 and EIP-7514.

Why “Dencun”?

Upgrades to the consensus layer use star names, and those to the execution layer follow Devcon city names. “Dencun” is the combination of Deneb, a first-magnitude star in the Cygnus constellation, and Cancun, the location for Devcon 3.

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Thank you to everyone who helped bring the blobs into existence, (nearly) rid us of SELFDESTRUCT and generally deliver one more major overhaul to the Ethereum network .oO!

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Original cover image by Darren Lawrence, with modifications by Tomo Saito.