This document describes the new features of MQSeries V5.2, including performance enhancements, MQSeries for Linux, application programming enhancements, the MQCMD_LEVEL_520 CommandLevel value, MQRFH2 - Version 2 rules and formatting header, processing of CodedCharSetId fields in MQSeries headers, C++ support for MQCNO Version 2 and Version 3, and applications using the IMS bridge.