This document outlines the technical process for upgrading the Aave V3 protocol from version 3.6 to version 3.7 across various networks.

The upgrade is executed via a single UpgradePayload contract deployed on each network.

1. New implementations: New implementations for the Pool and PoolConfigurator contracts are deployed, incorporating v3.7 features and optimizations.
2. Upgrade payload: UpgradePayload contains the sequenced steps to orchestrate the upgrade on all networks.
3. Deployment scripts: A single Forge script (Deploy.s.sol) per chain deterministically deploys the new implementation contracts, the upgrade payload, the AaveV3ConfigEngine, and a new UiPoolDataProviderV3.

Before upgrading the implementations, the payload cleans up reserve configuration flags and settings that are removed in v3.7. For each reserve:

1. Reset debtCeiling: If a reserve has a non-zero debt ceiling, it is set to zero via setDebtCeiling(reserve, 0). This also resets isolationModeTotalDebt to zero.
2. Disable borrowableInIsolation: If a reserve has borrowableInIsolation enabled, it is set to false via setBorrowableInIsolation(reserve, false).

Additionally, if a sequencer uptime price oracle sentinel is configured, it is unset via setPriceOracleSentinel(address(0)), as this feature is removed in v3.7.

These cleanup steps use the v3.6 interfaces to interact with the pre-upgrade contracts.

After the cleanup, the payload upgrades the core protocol contracts:

1. Upgrade Pool implementation: The Pool contract proxy is updated to point to the new v3.7 implementation via POOL_ADDRESSES_PROVIDER.setPoolImpl(POOL_IMPL).
2. Upgrade PoolConfigurator implementation: The PoolConfigurator contract proxy is updated to the new v3.7 implementation via POOL_ADDRESSES_PROVIDER.setPoolConfiguratorImpl(POOL_CONFIGURATOR_IMPL).