615 Series Protection Relays Firmware Update 4.1.9 Release Note

This document is a release note detailing firmware update 4.1.9 for ABB's 615 series protection relays (REF615, REM615, RET615, REU615, RED615), which includes a critical cyber security fix for CVE-2021-22283 (MMS file transfer vulnerability) and improvements to engineering and communication. It also summarizes the previous release 4.1.8, which addressed Ripple20 vulnerabilities (CVE-2020-11907 through CVE-2020-11912), a time counter rollover issue causing relay self-reboot, and GOOSE communication improvements.