Hi @osterhult, sorry no new updates here 
We do not have people using M1 internally (another reason we are keen to upgrade tensorflow). We cannot upgrade to 2.4 due to a bug that was fixed in 2.5. We are now evaluating performance decreases that we are seeing with 2.5 do determine whether the tradeoff is reasonable. We have another issue in tensorflow’s repository to alert them of these performance decreases.
There is an issue tracking our attempt to upgrade here. You can follow this for more updates, but rest assured there will be updates to this forum post as well