Welcome to the Ethereum Shapella Upgrade!

EIPs & CL changes, PEEPanEIP, and a Watch party invite.

Ethereum blockchain is expecting Shapella Upgrade on April 12, 2023. It will be will activate on the Ethereum network at epoch 194048, scheduled for 22:27:35 UTC as announced in the mainnet announcement blog post by Ethereum Foundation.

“Shapella” is a derived upgrade name (Shanghai + Capella) to suggest two layers of the blockchain are being upgraded simultaneously.

Shapella is the first network upgrade since TheMerge. It will deploy changes to the Execution Layer with the Shanghai upgrade; whereas the Capella upgrade will bring some spec changes to the Consensus Layer.

Activating staked ETH Withdrawal

With the concept of network upgrade centered around a particular proposal, EIP-4895: Beacon chain push withdrawals as operations is the “anchor EIP” of the Shapella upgrade. This upgrade will deploy EIP-4895 on the Execution clients to enable the Withdrawal of staked ETH for Ethereum validators along with three other EIPs deployed on the mainnet.

Since the launch of the Beacon chain in Dec 2020, Ethereum staking is unidirectional. Users may stake ETH to become a validator, perform duties and earn rewards in their wallet. This upgrade will allow them to withdraw their ETH partially (rewards only) or fully (staked ETH+rewards).

This is the first opportunity to enable staked ETH withdrawal along with EVM changes and preparation of future protocol changes since the merge of the beacon chain (PoS) and Ethereum PoW chain in September 2022.

Shanghai upgrade will deploy 3 more Core EIPs on the Execution Layer.

EIP-3651: Warm COINBASE — Direct COINBASE payments are becoming increasingly popular but accessing COINBASE is overpriced because the address is initially cold under the access list framework introduced in EIP-2929 (Berlin upgrade). This proposal will warm the COINBASE address at the start of transaction execution making it cheaper for users.

EIP-3855: PUSH0 instruction — Many instructions expect offsets as inputs, which in a number of cases are zero. This proposal will introduce the PUSH0 (0x5f) instruction, which pushes the constant value 0 onto the stack. This is a useful feature upgrade for clients & contract developers.

EIP-3860: Limit and meter initcode — This is an extension to EIP-170, to limit the maximum size of initcode and ensure initcode is fairly charged (most importantly cost is proportional to initcode’s length). It will simplify EVM engines by the explicit limits and have a cost system that is extendable in the future.

Readers should be aware that the Shanghai upgrade on Execution Layer is accompanied by the Capella upgrade on Consensus Layer which will be upgraded at the same time.

Capella will introduce the following changes to Consensus clients:

• Full and partial withdrawals for validators
• BLSToExecutionChange messages, which allow validators using a BLS_WITHDRAWAL_PREFIX to update it to an ETH1_ADDRESS_WITHDRAWAL_PREFIX, a prerequisite for withdrawals
• Independent state and block historical accumulators, replacing the original singular historical roots

It is important to note that EIP-4895 introduces a system-level “operation” to support validator withdrawals that are “pushed” from the beacon chain to the EVM. Enabling withdrawal is only possible with the specs change at Consneus Layer.

The Shapella Upgrade specs also include a Meta EIP-6049: Deprecate SELFDESTRUCT.

EIP-6049 is only a deprecation warning. Client teams expect SELFDESTRUCT semantics to change in future network upgrades, but the opcode’s behavior remains unchanged in Shanghai. EIPs for the spec change at the protocol level are still under discussion.

PEEPanEIP

To provide an overview of the proposals involved, testing, and client preparation in the Shapella upgrade, Ethereum Cat Herders recorded multiple talks with authors and client developers.

The playlist includes talks by authors and implementers to explain why they are included in the Shapella Network upgrade. Other featured talks are:

• PEEPanEIP #94: Staked ETH Withdrawal (Testing) with Potuz & Hsiao-Wei Wang
• PEEPanEIP #97 — Shapella Testing & Tooling with Parithosh J. & Mario V.
• PEEPanEIP #99: EIP-4736: Consensus Layer Withdrawal Protection with Benjamin Chodroff
• PEEPanEIP #101: Builder API (Shapella) with Gajinder Singh

PEEPanEIP is an hour-long deep dive into Ethereum Improvement Proposals and upcoming changes. Highly recommend watching for a better understanding of the concept shared by the authors of the proposal. Also, available on Ethereum Cat Herders Podcast.

Watch Party

Shapella Watch Party

You’re invited to the Shapella Livestream party!

EthStaker & Ethereum Cat Herders are organizing an upgrade watch party. We hope to be joined by you and

• Protocol Researcher — Vitalik Buterin
• ACDE/ACDC coordinators — Tim Beiko & Danny Ryan
• EIP Authors — Alex Stokes, Alex Beregszaszi, Paweł Bylica, William Morriss.
• Testing team rep — Parithosh Jayanthi & Mario Havel
• Ethereum client teams
• EthStaker crew
• ECH community

We welcome the Ethereum community to the complete Proof of Stake Ethereum blockchain world. Stay tuned for upcoming upgrades & changes in the Ethereum ecosystem with Ethereum Cat Herders!

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Share your question, comments, and suggestions with me on Twitter. Thank you for reading 🙏.

— The Ethereum Cat Herders

PS: Original image by Unsplash.