There are a few libraries we can update for the 2.90.
[ ] OpenImageDenoise 1.2
[ ] OpenImageIO 2.1
[ ] Maybe: OSL 1.11/2.0 if it's released in time
[ ] Embree 3.9.0 (and enable TBB)
There are probably more that are worth upgrading, for example the image / audio / video loading libraries haven't been updated in a while and likely have useful bugfixes.