Solana Activates Alpenglow on September 28: Validators Must Upgrade

The Solana network is set to activate Alpenglow on September 28, 2026, according to the release schedule maintained by Anza. This activation will mark a significant change for validators and stakeholders, with some requiring action to upgrade their nodes.

The release schedule lists five milestones leading up to feature activation: upgrading mainnet-beta on September 4, calling for volunteers to move 10% of the stake onto v4.3 on September 8, and a general recommendation to switch to v4.3 on September 21. Feature activation begins on September 28.

A key detail in the schedule is that a week lies between the general recommendation and activation, allowing for a buffer to ensure the majority of stake is already running the new implementation before the feature gate is thrown.