API: The database API no longer exists and has been replaced with Doctrine.
New Web: Icinga Reporting is now a fully integrated Cronk, delivered with this release.
Core & Classic UI: Performance tuning and enhancements to existing features – best to view our running change log/road map for the specifics.
Also, there are a few changes of special note for packagers to heed.
We hope you like the new features, and as this is a Beta release – please share any bugs you find on our development tracker https://dev.icinga.com.
Your feedback will ensure that Icinga 1.5 is as bug-free as possible in 14 days time. Thank you in advance!