Immutable X will hard fork its testnet on March 12
Immutable X will upgrade the Shanghai network.
The update is scheduled for March 12 and will be carried out on the zkEVM test network. The main goal of the update is to preserve and strengthen the connection between the Immutable zkEVM powered by Polygon and Ethereum.
You can find more detailed information in the official IMX tweet
Immutable X is a Layer 2 (L2) solution for increasing scalability of non-fungible NFT tokens
on the Ethereum network with instant trading and zero gas fees - all without compromising the security of users or their assets.