Lookup historic account data for a particular round has been dropped?

Hi all, has this feature been dropped? Shouldn’t it be somehow marketized towards the users before publishing to public indexer nodes?

returns now

  "message": "Unknown parameter detected: round"

Funny thing is that algoexplorer swagger still shows the round as a field.

Anyone has any advise how to detect the balance of specific asa at specific round for 1000 accounts?