The first release candidate for WordPress 4.5 was released on 24th March and the second release candidate (RC2) was released yesterday. Release candidate means that the new version of WordPress is fully completed and about to release. But, due to millions of users & thousands of plugins, there is a chance that WordPress team may have missed something.
In order to tackle with this issue, beta version and release candidates are released. The final release of WordPress 4.5 is expected to be out in the market by Tuesday, 12th April.
If you want to test the beta version of WordPress 4.5, go to its website and download the beta version. Another way of testing is that you can use WordPress Beta Tester plugin. If you have found any bug during the testing, then you can report it in the Beta Support Forum of WordPress.
In the second release candidate, the following changes were made:
- Normalized non-slashing of data in the REST API infrastructure.
- Customizer settings for widget instances get registered a bit later to give a chance for the widget instances themselves to be registered first.
- Fixed various cropping issues in the Custom Logo feature and Twenty Fifteen / Twenty Sixteen themes.