You can get the version information string of Kirikiri itself.
The version information string is longer than System.versionString and looks like this:
KiriKiri [Kirikiri] Z Execution Core /1.0.0.0 (Compiled on Dec 16 2013 23:15:27) TJS2 / 2.4.28 Copyright (C) 1997-2013 W.Dee and contributors All rights reserved.