WordPress 4.5 is coming up! Peruse this guide for the developer-focused changes  https://make.wordpress.org/core/2016/03/30/wordpress-4-5-field-guide/.

Pay attention to Backbone and Underscore being updated. Might break your scripts (e.g Add button in media library #35853), so make sure to test your code. While you’re at it, it’s even better to test other parts of your plugins and themes with the rest of the changes included in this release. 🍷