This proposal aims to upgrade the Snowbridge [Gateway](https://etherscan.io/address/0x27ca963c279c93801941e1eb8799c23f407d68e7) contract on Ethereum, which is remotely governed by OpenGov utilizing Snowbridge itself as a cross-chain governance bridge.

# New Features

The upgraded gateway supports new user-facing features:

* Tighter XCM integration allowing users to send a user contructed XCM message from Ethereum to Polkadot.
* Arbitrary message passing between Ethereum and Polkadot via XCM Transact.
* Un-ordered message delivery.
* Lower fees: all fee related calculation is moved offchain and is now dynamically calculated based on live gas prices.

# Technical Details

This proposal will update the Gateway proxy at [0x27ca963c279c93801941e1eb8799c23f407d68e7](https://etherscan.io/address/0x27ca963c279c93801941e1eb8799c23f407d68e7) with a new implementation contract at \[0x8a887783e945233d51881e06835ec78a8b575ece]\(https://etherscan.io/address/0x8a887783e945233d51881e06835ec78a8b575ece#code.

This contract was built and deployed using:

* Repository: [https://github.com/Snowfork/snowbridge](https://github.com/Snowfork/snowbridge)
* Commit: \[8662d76740960aee660487221712f1537274ddb5]\(https://github.com/Snowfork/snowbridge/commit/8662d76740960aee660487221712f1537274ddb5)
* Command: `cd contracts; scripts/deploy.sh contracts/scripts/upgrade/DeployGateway202509.sol`

# Testing

The upgrade proposal was extensively tested using simulations on forked instances of both Polkadot and Ethereum mainnet. This was done using Chopsticks and Foundry for Polkadot and Ethereum respectively.

Since the Ethereum side of snowbridge has no fallback governance or centralized escape hatches, it is critical to ensure that the upgrade does not affect the ongoing viability the gateway. In this regard, the fork tests in \[ForkUpgrade202509.t.sol]\(https://github.com/Snowfork/snowbridge/blob/8662d76740960aee660487221712f1537274ddb5/contracts/test/ForkUpgrade202509.t.sol) verify that cross-chain signalling is preserved.

# Audits

The Ethereum contracts were audited at revision `9bcac977155belbe0fc55e2d16ac3244667a50f4`, which includes the features described above. \[Oak Security Audit report]\(https://github.com/oak-security/audit-reports/blob/main/Snowbridge/2025-05-29%20Audit%20Report%20-%20Snowbridge%20v2%20v1.0.pdf)

#1763 Upgrade Snowbridge Gateway Contract