The last stable release is GtkSourceCompletion 0.5.2. Download
Current development version. The mayor library version has changed to GtkSourceCompletion-2.0 because I have changed the main API with the new GscCompletion object to do it easier.
This is the last release before GtkSourceCompletion-2.0 with the new GscCompletion object instead the current GscManager and GscPopup.