The recordIdsReplicated field has not been used in ASC so far; it is only relevant in DSC, where it needs to be set to true. This field was originally introduced in SERVER-78344 as a parameter in collectionOptions. During conversion to BSON, the recordIdsReplicated field was only included if its value was true.

SERVER-120943 removed recordIdsReplicated from collectionOptions, but DSC clusters currently in internal Beta currently have data that contains them. Therefore, to avoid crashing when using existing data after the changes from SERVER-120943, that ticket ensured that collectionOptions can parse and safely ignore the recordIdsReplicated field.

In the past, when transitioning toward DSC Private Preview, we took the opportunity to purge all DSC data and rebuild the clusters from scratch, which allowed us to introduce backward-incompatible changes in a simpler and more efficient manner. Should another similar opportunity arise, we can completely clean up the parsing logic for the recordIdsReplicated field in collectionOptions, as it will no longer be needed..