* Added missing jQuery UI sprite files, causing collectstatic to throw errors (most reported on Heroku)
* Page system check for on_delete actions of ForeignKeys was throwing false positives when page class descends from an abstract class (Alejandro Giacometti)
* Page system check for on_delete actions of ForeignKeys now only raises warnings, not errors
* Fixed a regression where form builder submissions containing a number field would fail with a JSON serialization error
* Resizing an image with a focal point equal to the image size would result in a divide-by-zero error
* Focal point indicator would sometimes be positioned incorrectly for small or thin images
* Fix: Focal point chooser background color changed to grey to make working with transparent images easier
* Elasticsearch configuration now supports specifying HTTP authentication parameters as part of the URL, and defaults to ports 80 (HTTP) and 443 (HTTPS) if port number not specified
* Fixed a TypeError when previewing pages that use RoutablePageMixin
* Rendering image with missing file in rich text no longer crashes the entire page
* IOErrors thrown by underlying image libraries that are not reporting a missing image file are no longer caught
* Fix: Minimum Pillow version bumped to 2.6.1 to work around a crash when using images with transparency
* Fix: Images with transparency are now handled better when being used in feature detection

Upgrade considerations
======================

Port number must be specified when running Elasticsearch on port 9200