Zikula Core 1.4.0 "Overture" is available as of today, 25 July, 2015.
More than four years have passed since the initial Zikula 1.3.0 release. More than 1400 issues have been opened and fixed during the 1.4.0 development. Since we released the first 1.4.0 release candidate in Februrary, more than 500 commits have been made to fix further bugs. A few days ago, release candidate 5 was voted to be the final 1.4.0 release.
Only very few backwards compatibility breaks were introduced (nothing compared to the 1.2.x to 1.3.x update) and most can be fixed with only a few minor adjustments. Further blog posts about upgrading, new features and future plans will be created over the next few weeks. By the way, http://zikula.org already uses a few months old development version of Zikula 1.4.0 and will be upgraded to the final release in the next few weeks. Dizkus has been rewritten and updated to work with Zikula 1.4.0 (including full upgrade from Zikula 1.2.x). It will be released soon.
Zikula Core 1.4.0 is intended as a transition release between the very popular 1.3.x series and Zikula Core 2.0.0. While maintaining nearly 100% backward-compatibility, 1.4.0 lays the foundations of Symfony, Doctrine, Bootstrap, Font-Awesome, jQuery and Twig which will be the basis of future development. A new namespaced module structure is established that will be the new standard for 2.0.0 extensions as well as providing many new tools and features to make your site exceptional.
As always, please report all bugs, concerns and feature requests to our issue tracker on Github. If you don't want to create a GitHub account, don't hesitate to ask in the comments or forums at zikula.org.