Infura’s Eth2 API was recently updated with endpoints to support the Altair hard fork.
However there are several
/v1/ APIs required for Altair which don’t seem to be exposed yet:
/v1/ APIs do seem to be present:
A full list of APIs added in v2.0.0 of the API is here: https://github.com/ethereum/beacon-APIs/releases/tag/v2.0.0