This is a maintenance release that's exactly the same as 6.10.0, reverting everything that was released in 6.11.0 and 6.11.1 which inadvertently introduced a BC break affecting child classes. Apologies for the mix up.
Important
If you have code that depends on the changes that were in 6.11.0 and 6.11.1, please upgrade to 7.0.0 instead.
Full Changelog: v6.11.1...v6.12.0