This proposal upgrades the Astar Network to runtime 1600, introducing support for asynchronous backing, applying a storage migration to the Democracy pallet, and fixing a critical issue in voting stake calculations during staking changes. This is a runtime-only release — no client changes are required.

🔧 Key Changes in Runtime 1600

✅ Async Backing

Reduces block time from 12s → 6s by enabling async backing, allowing parallelization between block production and parachain validation. This change significantly boosts block throughput and network responsiveness.

📌 All necessary constant updates and migrations have been implemented to safely activate async backing (#1481).

✅ Democracy Pallet Migration

Migrates all block number-related fields in the Democracy pallet to ensure compatibility with updated data structures and upcoming governance features:

• Migrated fields:
  • Referendum end and delay
  • PriorLocks inside Voting for all accounts

📌 This migration improves the integrity and consistency of on-chain governance scheduling (#1471).

✅ Fix: Voting Stake Discrepancy During Unstake/Move

Corrects an accounting bug in EraInfo that inflated the voting stake under specific conditions during unstaking or moving:

• Previously, total stake was subtracted using a flawed aggregation method.
• Now uses a dedicated subtract_stake method to handle voting and build-and-earn stakes separately.
• Extended this logic to ContractStake for smart contract staking consistency.
• Moved stake transformation logic into the SingularStakingInfo flow during move operations.

📌 Includes a test (era_info_stakes_remain_synced) that reproduces and verifies the fix (#1476).

🔄 Other Changes

• Merged release/patch-1501 into master (#1479)
• CI cleanup: removed aarch64 build (#1473)
• Inflation parameter adjustments (#1441)
• Dev dependency update: Vite v5.4.19 in E2E tests (#1469)
• Release template improvements (#1480)

🔗 GitHub Release – Astar Runtime 1600