- This update includes all bug fixes as well as security fixes in the previously released critical updates since DSM 5.2-5592.
- Improved stability of FTP connections.
- Improved stability when copying large files on DS216play.
- Improved general stability of NTP service.
- Supports Data Scrubbing for iSCSI LUN (Block-Level) in Storage Manager.
- Improved the stability of encrypted backup in models with ARM processors.
- Improved general stability of Btrfs file system.
- Increased the connection limit for Log Receiving in Log Center.
- Upgraded PHP to 5.5.30 to address multiple vulnerabilities (CVE-2015-5589, CVE-2015-5590, CVE-2015-6834, CVE-2015-6835, CVE-2015-6836, CVE-2015-6837, CVE-2015-6838, and CVE-2015-3152).
- Fixed an issue where a DSM critical patch could not be manually uploaded when the system was in a Hybrid HA cluster.
- Minor bug fixes.