virtualbox[.]org
This has a small changelog, and still doesn't fix the issue with the newer secure boot certificate not working, but it does include a bug that will effect almost nobody... the Guest Additions are incompatible with Win10 32-bit guests. In fact they brick Windows. The Guest Additions ISO from the Development Snapshots does work.
virtualbox[.]org/wiki/Testbuilds
This is a maintenance release. The following items were fixed or added:Windows Guest: Added DX11 performance improvements and fixes
Linux Host: Fixed kernel panic (github:gh-711, github:gh-712)
Linux Host and Guest: Fixed various NASM build issues (github:gh-520)