We're excited to introduce the v2.2 upgrade for USDC and EURC, delivering significant improvements in gas efficiency, security enhancements, and better support for account abstraction across EVM blockchains. This upgrade continues Circle's commitment to innovation following USDC's recent expansion to multiple blockchain networks.
Key Enhancements in v2.2
1. Smart Contract Wallet Signature Validation
- Implements EIP-1271 standard for smart contract wallet support
- Enables account abstraction for simplified user experiences
- Allows gas fee payments in USDC/EURC through smart contract wallets
- Supports permit, transferWithAuthorization, and related functions
👉 Discover more about smart contract wallets
2. Optimized Blocklisting System
- Reduces gas costs by 6-7% for common operations
- Improves efficiency of transfer, burn, and mint functions
- Maintains same security standards while lowering fees
| Function | Gas Savings | Cost Reduction |
|---|---|---|
| transfer | 7.18% | $0.11 |
| transferFrom | 6.55% | $0.12 |
| burn | 3.79% | $0.06 |
| mint | 3.02% | $0.06 |
3. Enhanced Fork Resilience
- Dynamic chainID inference prevents misuse on unofficial forks
- Protects users during blockchain network splits
- Automatically verifies official chainID
4. Removed Redundant Blocklist Checks
- Eliminates unnecessary blocklist verification for approval functions
- Achieves additional 7.34% gas savings for approve function
- Reduces costs for allowance adjustments
5. ERC-4337 Compatibility
- Skips timestamp check when deadline set to maximum value
- Enables account abstraction compliance
- Follows Ethereum community recommendations
6. EURC Symbol Standardization
- One-time update from "EUROC" to "EURC"
- Aligns with Circle's naming conventions
- No future symbol changes planned
Rollout Schedule
November 2023:
- Avalanche Fuji testnet (11/9)
- Avalanche mainnet (mid-November)
Late November - December 2023:
- Arbitrum testnet/mainnet
- OP testnet/mainnet
- Base testnet/mainnet
- Polygon testnet/mainnet
January 2024:
- Ethereum testnet/mainnet
- TRON testnet/mainnet
- Sepolia testnet support
👉 Learn about blockchain network upgrades
FAQ Section
Q: Do I need to take any action for this upgrade?
A: No developer or user action is required—the upgrade is fully backwards-compatible.
Q: How were the gas savings calculated?
A: Savings estimates come from Circle's simulations using Ethereum blockchain parameters (20 Gwei gas price, $1,700 ETH).
Q: Is the security audit available publicly?
A: While the full audit isn't public, it was conducted by Halborn, a respected blockchain security firm.
Q: Will EURC holders notice any changes?
A: Beyond the symbol update in contract code, EURC functionality remains unchanged.
Q: How can developers provide feedback?
A: Join Circle's Discord community to discuss the upgrade and implementation details.
Community Contributions
USDC v2.2 incorporates valuable input from:
- Alex Kroeger's gas efficiency suggestions
- Various external contributors via GitHub PRs
- Ethereum community recommendations
Special thanks to all who helped make USDC and EURC more efficient and accessible protocols for internet money.