# \[CONSTITUTIONAL\] AIP: ArbOS Version 40 Callisto
**URL:** https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436
**Category:** Finalized AIPs
**Created:** [February 13, 2025, 1:55pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436 "2025-02-13T13:55:57Z")
**Posts on this page:** 20
**Page:** 2
### Author:  [@Tane](https://forum.arbitrum.foundation/u/Tane)
#### Post date: [February 25, 2025, 9:11pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/21 "2025-02-25T21:11:00Z")
We vote **FOR** the proposal on Snapshot.
We have reviewed EIPs to be included (and not included) in the Callisto upgrade and we find the rationale behind each decision clear and articulated. We are particularly excited about the EIP-7702 change to be included on Arbitrum One and Nova for users on those chains as we believe the change will drastically improve the user experience over time.
We have a couple of questions:
> [@Arbitrum](#):
>
> Please note that ArbOS Version 40 “Callisto” is a proposed upgrade that builds upon ArbOS version 32 which has been previously adopted by the ArbitrumDAO - this proposal increments the version number to 40 instead of 33 due to technical details that allow for better Orbit chain customizability as explained [here](https://docs.arbitrum.io/launch-orbit-chain/how-tos/arbos-upgrade#step-3-schedule-the-arbos-version-upgrade)
Even reading [the detailed document](https://docs.arbitrum.io/launch-orbit-chain/configure-your-chain/common-configurations/arbos-upgrade#step-3-schedule-the-arbos-version-upgrade), it wasn’t clear what the “technical details” are and why this change better serves the Orbit chain customizability. Could you clarify them?
> [@Arbitrum](#):
>
> While the goal of the proposed ArbOS 40 “Callisto” upgrade is to eventually be available for adoption by any Arbitrum Chain, this proposal only concerns the Arbitrum One and Arbitrum Nova chains
While it makes sense that the proposal currently targets only Arbitrum One and Nova, how will these changes be adapted and applied to Orbit chains going forward?
---
### Author:  [@Euphoria](https://forum.arbitrum.foundation/u/Euphoria)
#### Post date: [February 26, 2025, 9:14am UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/22 "2025-02-26T09:14:47Z")
The following reflects the views of the Lampros DAO governance team, composed of Chain\_L (@Blueweb), @Euphoria, and Hirangi Pandya (@Nyx), based on our combined research, analysis, and ideation.
We are voting FOR this proposal in the Snapshot voting.
We support the ArbOS 40 Callisto upgrade as it ensures Arbitrum stays in sync with Ethereum’s upcoming Pectra upgrades and key EIPs. This upgrade will improve functionality, security, and developer experience while keeping the ecosystem efficient and future-ready.
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### Author:  [@BlockworksResearch](https://forum.arbitrum.foundation/u/BlockworksResearch)
#### Post date: [February 26, 2025, 5:56pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/23 "2025-02-26T17:56:12Z")
Blockworks Advisory is voting FOR this proposal.
We don’t see anything particularly wrong with these changes and believe them to be helpful to the future of the Arbitrum network. All these EIPs are helpful and have been brought to attention either in other discourse domains or directly through Arbitrum forums (like the historical block hash change).
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### Author:  [@danielM](https://forum.arbitrum.foundation/u/danielM)
#### Post date: [February 26, 2025, 6:06pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/24 "2025-02-26T18:06:41Z")
I am voting for this proposal because it will upgrade Arbitrum to support important new Ethereum features, like letting normal accounts run smart contracts and improving security with better cryptography. Arbitrum needs to correspond to his L1. And this proposal will help to implement it. It’s very good that the developers also don’t forget about Arbitrum Nova. I definitely vote for
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### Author:  [@Griff](https://forum.arbitrum.foundation/u/Griff)
#### Post date: [February 26, 2025, 6:33pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/25 "2025-02-26T18:33:04Z")
I’m VOTING YES! This AIP keeps Arbitrum aligned with Ethereum’s innovations while strengthening our security and empowering builders. Who would vote against this?
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### Author:  [@0x\_ultra](https://forum.arbitrum.foundation/u/0x_ultra)
#### Post date: [February 26, 2025, 6:44pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/26 "2025-02-26T18:44:32Z")
I’m voting in favor of this proposal cause I feel like it only makes sense to support necessary upgrades like these, Arbitrum should keep up with EIPs.
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### Author:  [@tamara](https://forum.arbitrum.foundation/u/tamara)
#### Post date: [February 26, 2025, 11:05pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/27 "2025-02-26T23:05:31Z")
Voting in favor. I have no technical background but from a logical POV/overall understanding it makes sense that some changes are needed with Pectra + I am trusting the AF on this.
The time lag struck me as odd, which is why I would love to see the question below answered.
> [@cp0x](#):
>
> Can something not work correctly in Arbitrum if the Ethereum network is already updated, but Arbitrum is not?
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### Author:  [@Linzerd](https://forum.arbitrum.foundation/u/Linzerd)
#### Post date: [February 27, 2025, 12:53am UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/28 "2025-02-27T00:53:21Z")
The proposed changes help to bring Pectra relevant modifications to Arbitrum, and also advance account abstraction in the ecosystem. In this sense, I see no reason to oppose this initiative, as it seeks to bring new technical possibilities for users.
EIP-7702 is especially interesting from a defi perspective because it brings new capabilities to the wallet and smart contract ecosystem, specifically batching. I expect these to be applied to Orbit chains in a subsequent update.
The proposal has a low risk associated, with any kinks being ironed out during the test period in Devnets and Sepolia. Voting FOR this one.
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### Author:  [@Bob-Rossi](https://forum.arbitrum.foundation/u/Bob-Rossi)
#### Post date: [February 27, 2025, 3:26am UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/29 "2025-02-27T03:26:13Z")
Voting “For”, as I have stated in other upgrades like this - while I am not technically proficient enough to do a deep dive review on these types of things… I trust the teams involved with this project and the capable minds of the DAO to dive into those items. At a 10,000 foot glance, the upgrades seem worth implementing and I generally favor any upgrades that continue to keep Arbitrum at the forefront tech-wise.
Edit: In order to save forum space, I will just confirm my “Yes” vote on Tally. Nothing in my opinion has changed since February’s temp check
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### Author:  [@paulofonseca](https://forum.arbitrum.foundation/u/paulofonseca)
#### Post date: [February 27, 2025, 11:03am UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/30 "2025-02-27T11:03:04Z")
voting **Abstain** on the current offchain vote because I have no idea of the risks this upgrade will entail without seeing the results of an independent audit to the smart contract code. And I also think the governance process for this proposal has not been followed in the best way it could. I think the Arbitrum DAO delegates should be asked to vote, even on a temperature check, in as much of a fully fleshed out proposal, as possible. This proposal is not ready to be voted on by delegates, in my opinion, in the sense that if delegates vote against in this temp check, will the work on this upgrade stop? No, it won’t. So I don’t understand why delegates are being asked to vote on this proposal, at this point. After the code is complete and the audits are done, then it makes sense for delegates to decide on the risk vs. reward of upgrading the Arbitrum One and Nova contracts, with this proposal.
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### Author:  [@shogun](https://forum.arbitrum.foundation/u/shogun)
#### Post date: [February 27, 2025, 12:04pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/31 "2025-02-27T12:04:47Z")
_ **The following reflects the views of GMX’s Governance Committee, and is based on the combined research, evaluation, consensus, and ideation of various committee members.** _
We are in **favour** of this proposal.
With the advent of Spectra and its technical changes, ArbOS Callisto aims to devise an upgrade that will definitely create added value for the ecosystem. Especially so for account abstraction applications. The utilisation of Spectra’s upgrade — incorporating transaction sponsorships for covering user gas expenses with auth signatures, batching transactions to eliminate additional user friction for using apps (like having to pay for approvals and do a trade), and privilege de-escalation — can reduce security risks for users.
Additionally, the other upgrades are very clear: EIP-2537 for improved security for applications, EIP-2935 serving the data retrieval of block hashes to configure on top of clients, and Stylus fix amount to a reasonable request.
Noting that there are technical considerations pertaining to the various environments (into Nitro) and sequence of implementations (for audits and test developments), we do believe that this effort is worthwhile and will be completed diligently. Therefore, we are for **approval** of the proposal.
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### Author:  [@ocandocrypto](https://forum.arbitrum.foundation/u/ocandocrypto)
#### Post date: [February 27, 2025, 3:40pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/32 "2025-02-27T15:40:08Z")
As in @web3citizenxyz representation. Voting FOR. Below the rationale:
> [@Web3 Citizen Delegate Communication Thread](https://forum.arbitrum.foundation/t/web3-citizen-delegate-communication-thread/27518/29):
>
> Snapshot: Arbitrum OS Callisto We are voting FOR this proposal We are in favor of the proposed upgrade to support Pectra. We are relying on the provided explanations for including or excluding EIPs, though we did [seek clarity](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/3) on potential issues regarding calldata cost differentials. Based on our understanding, we see no reason not to support this proposal.
---
### Author:  [@pedrob](https://forum.arbitrum.foundation/u/pedrob)
#### Post date: [February 27, 2025, 3:43pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/33 "2025-02-27T15:43:35Z")
I vote in favor of this proposal in the temp check, as I believe it is crucial for Arbitrum to be ready for the Pectra fork on Mainnet. However, my on-chain vote will depend on analyzing—within my capabilities and relying on the assessment of technical experts—the progress of the outlined roadmap.
> [@Arbitrum](#):
>
> More detailed information about the specific implementation and versions will be provided closer to the date of the formal on-chain Tally vote. However, this proposal will roughly follow the below steps:
>
> 1. An AIP outlining the proposed upgrade and specification is proposed to the ArbitrumDAO Forum for discussion (this post)
> 2. A temperature check vote is held on Snapshot
> 3. Engineering work to scope out and implement the relevant changes for ArbOS 40 Callisto into the Nitro node software, relevant rollup contracts, and associated upgrade actions (this work has already begun).
> 4. A security audit of all ArbOS 40 relevant changes is conducted by a third-party (Trail of Bits) and the audit report is published for public consumption.
> 5. A new version of Nitro and nitro-contracts is released that support ArbOS 40 Callisto.
> 6. Should the Snapshot vote pass, then ArbOS 40 Callisto will be deployed to both private devnets & Arbitrum Sepolia for testing.
---
### Author:  [@Juanrah](https://forum.arbitrum.foundation/u/Juanrah)
#### Post date: [February 27, 2025, 3:49pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/34 "2025-02-27T15:49:20Z")
I will be voting FOR in Snapshot. I believe Arbitrum should continue to be aligned as much as possible with Ethereum, and we should also leverage the position Arbitrum has within the ecosystem in this regard.
We should thoroughly follow every upgrade made in Mainnet and be as prepared as possible for its correct implementation.
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### Author:  [@Bobbay](https://forum.arbitrum.foundation/u/Bobbay)
#### Post date: [February 28, 2025, 12:06am UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/35 "2025-02-28T00:06:28Z")
lets goooooo. I am excited for this upgrade! 7702 will unlock some cool usecases. Voting in favour here!
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### Author:  [@lobbyfi](https://forum.arbitrum.foundation/u/lobbyfi)
#### Post date: [February 28, 2025, 10:53pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/36 "2025-02-28T22:53:37Z")
LobbyFi voted abstain on snapshot since none of the community pools reached the needed threshold, which is at 10% of the instant buy which has been chosen for this proposal.
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### Author:  [@olimpio](https://forum.arbitrum.foundation/u/olimpio)
#### Post date: [March 2, 2025, 11:13pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/37 "2025-03-02T23:13:55Z")
I voted for to this proposal, I’m in favour of keeping ARB and ETH’s roadmaps aligned.
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### Author:  [@WinVerse](https://forum.arbitrum.foundation/u/WinVerse)
#### Post date: [March 3, 2025, 1:49pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/38 "2025-03-03T13:49:22Z")
DAOplomats voted FOR this proposal on Snapshot.
This AIP brings essential Ethereum Pectra changes while maintaining Arbitrum’s unique optimizations. Plus, EIP-7702 is a game-changer for EOAs, enabling account abstraction natively so we were happy to support this update.
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### Author:  [@Frisson](https://forum.arbitrum.foundation/u/Frisson)
#### Post date: [March 3, 2025, 11:51pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/39 "2025-03-03T23:51:47Z")
I voted FOR this proposal at the temp check stage. I’m excited about Pectra because I think it will significantly improve Arbitrum UX by reducing the need for multiple signatures to perform a single transaction and by allowing Dapps to enable more advanced functionality directly e.g. paymaster support.
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### Author:  [@cp0x](https://forum.arbitrum.foundation/u/cp0x)
#### Post date: [March 7, 2025, 7:15pm UTC](https://forum.arbitrum.foundation/t/constitutional-aip-arbos-version-40-callisto/28436/40 "2025-03-07T19:15:44Z")
Will the Arbitrum upgrade be delayed due to the mainnet upgrade suspension?
> After two buggy test runs of Pectra, Ethereum’s biggest upgrade since 2024, the network’s developers decided to postpone the upgrade pending further tests
> **[Ethereum Developers Postpone Pectra Upgrade Following Buggy Tests](https://www.coindesk.com/tech/2025/03/06/ethereum-developers-extend-pectra-test-window-following)**
>
> After two buggy tests, Ethereum's developers have decided to spend a bit more time collecting data on the highly-anticipated Pectra upgrade.
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