From Splashtop Business app (v3400 or later)
Splashtop Business app / Help / About...
From Splashtop Streamer (v3400 or later)
Streamer / About
From SOS agent (v3400 or later)
SOS agent / Settings / About
From web console
my.splashtop.com or my.splashtop.eu
(The one in [] is the current region.)