According to Odaily, ZKsync has issued a notice on the X platform regarding a temporary compatibility issue during the protocol upgrade to version 26. The Mailbox contract, which initially handles L1 to L2 transactions, is experiencing backward compatibility problems due to the different transitional stages of bridging and L2 during the upgrade. This issue may take approximately 1.5 to 2 weeks to resolve. Users are advised to use 'requestL2TransactionDirect' and 'requestL2TransactionTwoBridges' on BridgeHub instead of Mailbox. Additionally, ZKsync recommends migrating to BridgeHub to avoid potential deprecation of the Mailbox contract in the future.