In the recent update of K2 v2.7.0 we decided to decouple any built-in integration with third party extensions for 2 important reasons: easier maintenance of third party features and faster updates.
K2 is built as a solid component and we don't plan on releasing updates every couple of weeks. To give you an idea of how solid K2 is, the previous version (2.6.9) was released in December 2014 and it was 100% compatible with Joomla 3.4.x up until the launch of K2 v2.7.0. A slower release cycle means we are more careful when we issue updates to K2 and this is something we believe firmly.
That being said, if we want to properly support third party extension integration with K2, it's best to decouple any such functionality. It's what we did since the inception of K2 in 2009 when we decided to keep the advanced media and image gallery functionalities completely separate in the form of AllVideos and Simple Image Gallery Pro.
After so many years, one thing has also proved certain: the continuous support of sh404SEF from Anything Digital and recently from Weeblr (founded by sh404SEF's original developer, Yannick Gaultier). sh404SEF is one of the most popular extensions in the Joomla community and it's arguably the best SEO related extension for Joomla.
So seeing sh404SEF continuously being updated and improved, we decided to decouple it from K2 in order to follow such changes in sh404SEF's development. As a bonus we also added community requested features for even better URL manipulation and finally we made sure the plugin supports both K2 versions 2.x and the upcoming 3.x. That's one codebase to maintain and from now on it will fall to faster updates, following closely the development of sh404SEF.
The new "K2 Plugin for sh404SEF" is distributed commercially for two reasons: we can provide dedicated/personal support and it's a way to give back to the K2 project.
"K2 Plugin for sh404SEF" is now available to purchase in 6 and 12 month subscriptions, starting from 14.90 EUR.