Invalid license keys: We have installed a new GuiXT version (2011 Q3 2) and now our license keys for "InputAssistant" and "Viewer" in guixt.ini no longer work. Do we need new license keys for this version?

Your license keys are still valid. You probably did not specify the licensed components in guixt.ini.

If this is the case GuiXT assumes that all components are selected. Since a further component "GuiXT Controls" now exists, a license key that includes "GuiXT Controls" would be needed. If you specify the components you purchased:

Component GuiXT
Component InputAssistant
Component Viewer

your license keys will work again.