# M09-L05 — Lab contract

**Build:** Deploy local proxy V1/V2 and test preserved storage layout.

**Pass:** V2 reads old balances; incompatible layout test detects risk.

**Failure injection:** Storage layout changes can corrupt balances.

**Review question:** How do timelocks and multisigs mitigate upgrade risk?

Status: specification; only count as executable when source and tests are present and verified.