Sei EVM Upgrade: Sei Network has issued a final deadline for exchanges and SEI custodians to migrate customer holdings as the protocol completes its transition to a unified Ethereum Virtual Machine (EVM)-only architecture. Under Sei Improvement Proposal-03 (SIP-03), any integration treating “Sei” (native) and “Sei EVM” as two separate chains must be reconciled into a single integration before the Cosmos and Inter-Blockchain Communication (IBC) shutdown on June 15, 2026.
Details on SIP-03 modifications
Every native Sei address (sei1…) has an equivalent EVM address (0x…) on the same chain. There are not two separate chains or wallets. For instance, address association is the explicit onchain link between them, without which funds held under the native address will not be accessible via EVM after CosmWasm (Cosmos WebAssembly) support is deprecated. This association must be completed before the deadline; afterward, no mechanism will exist to associate addresses.
Sei EVM upgrade: Four migration options
- Combine native and EVM access points: Here, surf the EVM address for each native wallet directly; requires no customer action or fund movement. This is the cleanest path.
- Automated forwarding contract: The exchange must deploy a FundsForwarder contract to programmatically move funds from native to EVM addresses.
- User-directed forwarding contract: Through this option, customers trigger the FundsForwarder contract themselves.
- Fully manual transfer: Customers withdraw to self-custody then redeposit to new EVM addresses.
FundsForwarder contract
On the other hand, the contract “FundsForwarder” has been audited by OtterSec; this contract is used to deposit tokens at native addresses and forward the full balance to a pre‑configured EVM destination. Some of the key properties include a fixed, unchangeable destination address. The contract is used to automate both user-directed and automated transfers of funds; however, when the contract becomes deprecated, no new deposits will be allowed.
What comes next
Post June 15, 2026, Cosmos-based transaction interfaces will no longer be available. No exchange will be able to send Cosmos format transactions. Address associations can no longer be created, nor will the FundsForwarder pattern support any new deposits.
This upgrade comes in time to compete with other blockchain upgrades from different networks, trying to improve its operational capabilities in line with today’s requirements, including infrastructure, privacy, and security.