Key Highlights
- Sei Network’s SIP‑3 upgrade in March 2026 will make USDC.n inaccessible or lose value.
- Holders must swap USDC.n to native USDC via DragonSwap, Symphony, or migration tools.
- About $1.4M USDC.n remains on Sei; timely migration is crucial to avoid asset loss.
The Sei Network has issued an urgent alert to holders of USDC.n, a legacy version of the USDC stablecoin, to swap or migrate their tokens before a major network upgrade planned for March 2026, warning that lingering balances could lose accessibility or value after the transition.
USDC.n, also known as USDC via Noble, was originally issued by Circle on the Noble blockchain and bridged to Sei as the primary dollar‑pegged stablecoin used on the network.
Since then, Circle has launched native USDC directly on Sei, which has made many users swap their bridged tokens to the canonical one. By early January 2026, the value of USDC.n on Sei had dropped to approximately $1.4 million, compared to several million holders who have moved off.
What’s happening and why it matters
The urgency stems from a forthcoming upgrade known as SIP‑3, which will convert Sei into an EVM‑only blockchain, a network that only supports Ethereum‑compatible tokens and smart contracts.
As part of this change, Cosmos‑native assets like USDC.n and other legacy tokens will no longer be supported. Anyone still holding USDC.n after the upgrade could find their tokens inaccessible or significantly devalued on the Sei Network.
“After this upgrade, USDC.n may become inaccessible or lose its value on the Sei Network,” the project said in its official announcement.
The SIP‑3 upgrade is expected to go live on mainnet at the end of March 2026, though the timeline may shift slightly depending on final testing and community governance outcomes. Holders are advised to follow official channels for updates.
How holders can convert
Sei’s guidance outlines different paths for holders: For smaller balances, users can swap USDC.n for native USDC using decentralized exchanges such as DragonSwap or Symphony. However, liquidity and slippage may vary, and holders should exercise caution and research before transacting.
For larger amounts, a batching and migration tool exists that moves USDC.n through Noble, then Polygon, and finally back to Sei using Circle’s Cross‑Chain Transfer Protocol (CCTP). Manual bridging methods are also possible but carry extra technical risk and potential for loss.
Sei’s advisory also notes that holders who have supplied USDC.n into lending or defi protocols like Yei or Takara Lend must first withdraw those positions before migrating, or risk loss of access when the SIP‑3 upgrade takes effect.
Context and recent developments
This alarm is in line with larger trends in the Sei ecosystem. In July 2025, Circle introduced native USDC and CCTP V2 on Sei to enhance liquidity and cross-chain transfers, which made native USDC the main stablecoin on the network.
The shift to an EVM‑only architecture mirrors industry trends toward Ethereum compatibility, with many chains standardizing around EVM tools and developer ecosystems.
The transition is expected to streamline development, enhance interoperability, and simplify token standards on Sei, but it also renders legacy Cosmos‑native assets obsolete.
To users of USDC.n, this is an alert that it may be necessary to keep up with protocol changes and timely migrations to protect crypto assets.
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