Stellar network upgraded to Protocol 16 on April 10, 2021 following a network incident. Node operators must update to Stellar Core v16.0.0 and Horizon v2.1.0 to restore service and rejoin the network.
On April 10, 2021 at 1500 UTC, Stellar network validators voted to upgrade the network to Protocol 16 in response to an April 6 incident that caused several nodes to go offline. The upgrade includes critical fixes in Stellar Core v16.0.0 and Horizon v2.1.0 to allow affected nodes to rejoin the network. Node operators must download and install these versions, with Horizon requiring a database migration. The post provides detailed upgrade instructions for both standalone and Captive Core architectures, plus recovery steps for stuck Horizon instances. Originally planned Protocol 16 features like Asset Clawback have been deferred to Protocol 17.
