I've just released and uploaded Smack 4.1.6 and 4.2.0-alpha3 to Maven Central.
Smack 4.1.6 contains a few important bug fixes for Smack's stable branch: 4.1. The changelog can be found here: Smack Changelog
The third alpha version of Smack's upcoming development branch contains a ton of fixes and new features. Adventurous users are encouraged to explore the API improvements. But, as the version name suggests, don't use an alpha version for production deployments. A provisional and incomplete list of Smack 4.2's highlights can be found at Smack 4.2 Readme and Upgrade Guide · igniterealtime/Smack Wiki · GitHub