Litecoin Core v0.21.5.5 released!
All users are advised to upgrade. This release contains important security updates.
— Litecoin Foundation ⚡️ (@LTCFoundation) May 7, 2026
The release also contains notable changes, including important MWEB validation and state-handling fixes.
The maximum P2P protocol message length was increased to 32 MB so that valid MWEB blocks and messages fit under the message-size limit. The release also prevents the reading of the previous block from disk when constructing HogEx transactions. This also avoids including MWEB transactions in candidate blocks when their input and output commitments would sum to zero.
Tests were added and expanded for MWEB P2P messages, duplicate pegins, crash recovery, mutated blocks, mining, and wallet/RPC behavior.
The MWEB PMMR rewind corruption was fixed alongside improved MMR file write durability. A transaction index consistency issue was fixed that could occur if writing block data failed after the index commit.