615 Series Protection Relays Firmware Update 4.0.8 Release Notes

This document details firmware update release 4.0.8 for ABB's 615 series protection relays (REF615, REM615, RET615, REU615, RED615), including usability improvements and a self-supervision watchdog enhancement. It also documents improvements from the previous release 4.0.7, which addressed Ripple20 cyber security vulnerabilities, supervision, protection, and communication stack issues.