No, Ubiquiti has since released newer firmware versions. However, the specific policies and partition layout introduced with v5.6 remain in place for newer builds.
Understanding Firmware Version Xw.v5.6.11: Features, Updates, and Installation Guide Firmware Version Xw.v5.6.11
Speeds up the loading time of the local administrative dashboard web interface. Step-by-Step Installation Guide No, Ubiquiti has since released newer firmware versions