"In terms of software, Satio uses the Symbian OS 9.4 operating system, which is created collaboratively under the stewardship of the Symbian Foundation as "Symbian^1".[4] It is Sony Ericsson's first non-UIQ Symbian device, after UIQ's development closed down earlier that year. It uses the PlayNow service, Sony Ericsson's mobile content platform, and is part of the company's new Entertainment Unlimited service.[5] In terms of connectivity, it is Wi-Fi-enabled and has a GPS chip for navigation and location-based services. It also supports full Flash for video playback.
They made a total of 2 devices with Symbian^1 (+1 refresh) before ultimately moving on to Android.
Symbian^1 was the attempt to harmonize the Symbian flavors into one open platform in order to compete, after Nokia, Sony Ericsson, Motorola and other contributed all IP into the Symbian Foundation.
Nokia called it "S60 5th Edition", for others it was "Symbian^1", and the first "common" Symbian OS.
So yes, I wasn't precise enough in the later comments, and you're correct.