Has anybody received notice that their federal refund has been approved yet?

Your e-filed return is still in pending on the server because the IRS will not begin to accept/reject/process returns until January 27.  Only a few returns were accepted early in a test batch.  Everyone else has to wait.

https://www.irs.gov/newsroom/irs-opens-2020-filing-season-for-individual-filers-on-jan-27

So watch your emails and spam folder to make sure you know after Jan. 27 if your return was accepted or rejected.

"Your e-filed return is still in pending on the server because the IRS will not begin to accept/reject/process returns until January 27.  Only a few returns were accepted early in a test batch.  Everyone else has to wait."

This is not exactly true.  My son received his refund yesterday.