Drupal has announced that it will release version 10.0.0 on December 14, 2022, with many breaking changes.
UPDATE: Release dates have been rescheduled to December according to this post. The post below contains outdated information.
Drupal 10 release
The first beta of Drupal 10 is expected to be released on 21st March 2022 while 10.0.0-rc1 will be released on 16th May 2022.
Drupal 10.0.0 is currently available in alpha1 which means most of the changes expected in 10.0.0 may not be available in the alpha1 version. Here are major changes to expect in the final version that will be released in June 2022.
- CKEditor 4 will not be available in Drupal core. This means you must update to CKEditor 5.
- Symfony will be updated from version 5.4 to 6.
- PHP 8.0 is required for Drupal 10 and 8.1 is supported
- Internet Explorer 11 will not be supported because more functionalities will stop working with Explorer 11
- Twig will be updated from 2.x to 3.x. You must have atleast PHP 7.2.5 to run Twig 3.x
- Guzzle will be updated from 6.5.2 to 7.3.0. It also requires alteast PHP 7.2.5