1.5 was a silent release mostly dealing with performance improvements.
1.6 adds annotations: text/ink tagging, and highlighting. Text annotations are indexed and can be searched using the "tag:" prefix. Handwriting recognition will be added for Ink annotations in a future release. Annotations can be added using some new icons at the bottom left of the two-pane reader. Text annotations can also be added by CTRL-T.
I uncovered a indexing problem where some items were not being removed from the index when deleted. 1.6 addresses this by rebuilding the entire index, so please be aware that this process can take several minutes on the first run.
Head over to the main RikReader page for download links.