# Review Code Changes (MANDATORY for each step)

After completing changes in each step, review code changes per the rules in the Progress Template BEFORE verification. Key areas:

- **Sufficiency**: All required upgrade changes are present — no missing modifications that would leave the upgrade incomplete.
- **Necessity**: No critical unnecessary changes. Unnecessary changes that do not affect behavior may be retained; however, it is essential to ensure that functional behavior remains consistent and security controls are preserved.