Use CMS as the version authority
CMS's RAI Manual page identifies the current manual and item-set materials and records corrections. Its technical-information page separately publishes data specifications and software-facing updates.
A downloaded PDF can therefore become stale while still looking official. Bookmark the CMS index, not only a local copy, and record when the reference was checked.
Inventory where MDS data enters the pharmacy workflow
List each imported, rekeyed, or reported MDS field; the source system; responsible owner; refresh cadence; and manual or item-set version assumed. Pay special attention to fields used in denominators, exclusions, resident risk views, and facility summaries.
This is data lineage, not a compliance certification. It helps the practice explain why two reports disagree and what must be retested after a specification change.
Give vendors a version-change test
Ask how a changed item is mapped, validated, released, and communicated. Request a sample showing the old value, new value, effective date, and effect on historical reports.
A promise to 'support MDS' is too broad for a buying decision. The useful answer names versions, data paths, responsibilities, and how corrections are handled.