615 Series IEC Protection Relays Firmware Release Notes 5.1.25

This document is a release note detailing firmware update 5.1.25 for ABB's 615 series IEC protection relays (including REF615, REM615, RET615, and others). It outlines implemented usability improvements, cyber security updates, HMI communication enhancements, and measurement stabilization, as well as changes from previous release 5.1.24 regarding supervision, RAM fault handling, frequency protection, and PTP time synchronization.