Domain data models such as the Vehicle Signal Specification are increasingly used as the shared source from which teams derive API schemas, streaming contracts, and database views across different technology stacks. Once these derived artifacts run in production, a change to the domain model becomes a contract compatibility problem: platform teams and downstream consumers often move at different speeds, and a rename or datatype change can break clients still running on an older release. Today's tooling tracks identity, change history, and contract versioning as separate concerns, so no single artifact ties all three together in a way that works across modeling languages. This talk introduces ModL, a Python-based CLI tool built within COVESA that maintains an append-only ledger alongside a domain model. The ledger separates four concerns: stable concept identity, unconditional revision history, policy-gated contract versioning, and runtime-addressable bindings, so different consumer teams can apply their own breaking-change rules to the same history without forking the audit trail. We will walk through the modl sync command validated against both VSPEC and S2DM, then demonstrate modl adapt in an EV charging scenario where a generated adaptation plan is translated into a MongoDB aggregation pipeline that serves clients still on an older contract. The talk closes with concrete next steps for COVESA members, including adopting the ledger alongside VSS and S2DM releases and plugging the tool's adaptation reports into existing CI pipelines.