Upgrading to this version from <= v2.8.3 will trigger a state rebuild. During this process (which will take at least 10 minutes), Horizon will not ingest new ledgers.

DB Schema Migration

• Added indexes by id for claimable balance and liquidity pool id's in the respective tx/ops tables. Ingestion will stop while the migration is being applied. (4455)

Changes

• Orphaned rows in lookup tables (history_accounts, history_claimable_balances and history_liquidity_pools) are removed in small batches after each ledger if --history-retention-count is set. (4518, 4525)
• Improve restart time of Captive-Core when started with --captive-core-use-db flag. The solution does not work on Windows. (4471)
• Fix a bug in which state verifier would run if condition checking DB query fails. (4523)