We recently ran across an issue where we merged 2 heterogenous OHDSI instances (inpatient/outpatient) into one database. Due to a previous failure, we found that one source had a stale/lagged Vocabulary. This clearly caused many concept discrepancies in our final product. A reload using consistent vocabulary can fix the problem. We also thought the relationship table might help us since the vocabulary is backward compatible. I would think all deprecated concepts are maintained and “mapped to” a new standard within a single hop but that is not that we found after a brief review. I also thought about incremental loads that over time may want to upgrade their vocabulary without a full reload. @DTorok I was told that you may have some valuable insight. Of course, we welcome feedback from anyone!