BAR - branch adapt route. Congrats and thank you, AI2, for this interesting approach. We've performed similar experiments, namely transplanting experts from a new LLM version (DS-V3-0324) to an earlier base mode (DS-V3). Domain-specific performance, such as on subsets of SimpleQA, can be improved selectively. Implanting more and more experts, e.g. up to 1% of total experts, steadily enhances benchmark performance. The selection method which experts to transplant is crucial.