Improvements since 8.1 can be discovered by reading this blog. Of particular note is the increment from 22.214.171.124 to 8.1.4, which has introduced more robust fault recovery:
Upgrade If you already have Quirky Xerus running on the Pi, an earlier version, upgrade to 8.1.4 is available by small Service Pack PET package.
Starting the Package Manager (PPM) will automatically probe for availability of a Service Pack, or run from the menu:
Filesystem -> Quirky Version Upgrade Manager