It’s been more than a year since we made a release, so there have been lots of changes, fixes and new features. Most important of all is the integration of the SIMPLE descriptor, a local feature that works extremely well for content based image retrieval. This has been done with a lot of help from Nektarios Anagnostopoulos and Savvas Chatzichristofis!
Besides that we switched to OpenCV for SURF and SIFT extraction, added numerous bug fixes, updated Lucene to 4.10.2 and much more. Best you give it a try.