Anza instructed all Solana mainnet-beta validators and operators to upgrade immediately to Agave v4.3 on September 21, the general adoption milestone before Alpenglow's targeted September 28 feature-gate opening. Anza CEO Brennan Watt confirmed 90 minutes later that v4.3.0 was approved for mainnet and linked the GitHub release. The release includes improved Votor-transport send-error statistics and two commission-management CLI commands, while the feature gate will initially activate Votor, Alpenglow's replacement for TowerBFT's voting mechanism. Votor targets finality of around 150 milliseconds versus roughly 12.8 seconds under TowerBFT and raises fault tolerance from 33% to 40% of stake. Validators remaining on Agave 4.2 through activation will be using unsupported software. The network has operated with 250-millisecond target slots since epoch 1037, but slot production and consensus finality remain separate mechanisms.