# Upgrading Pantheon

## Upgrading to v3.19.0

### Memory Persistence Protocol
Pantheon v3.19.0 introduces the Memory Persistence Protocol — a standardized system for how agents persist and recall memory.

Key changes:
- All 14 agent files now have a `## 🧠 Memory Protocol` section with mandatory rules
- Agents must call `memory_recall()` before work (top_k=3, skip if score <0.3)
- Agents must call `memory_store()` after work (2 lines max, importance 0.4-0.9)
- Zeus auto-stores on agent return — no extra work needed
- Session-end auto-save runs at session close
- Memory Bank is updated only at sprint close (importance ≥ 0.6 graduates)

**No manual migration needed.** The protocol is enforced at the agent instruction level.

### Previous Upgrades

For upgrading from versions before v3.19.0, see the CHANGELOG for version-specific changes.