I've upgraded the firmware using Uploader Tool
https://j3.rf-explorer.com/upgrade
The log now reports:
WARNING:Analyzer firmware version connected v01.34 is newer than the one certified v01.33 for this version of RF Explorer for Windows.
However, it may be compatible but you should check
www.rf-explorer.com website
to double check if there is a newer version available.
Anyway, RE is connected to the software and it is reading live data from the RE,
For me, it's ok, since I've installed just previously the latest version. I will wait for a new version of RF Explorer for Windows.