Solana is advancing two separate performance tracks: the Alpenglow consensus upgrade, which aims to cut cryptographic finality from roughly 12.8 seconds to about 150 milliseconds, and the SIMD-0525 slot-time program, which has now brought testnet to 250-millisecond slots with a reported 10,000 transactions per second at 236ms under synthetic load. Solana Foundation materials say Alpenglow is expected to activate with Agave 4.3, targeted for October 2026, while Agave 4.2 includes the full code for testing and hardening but will not switch mainnet to the new consensus system. That timeline conflicts with a newer report citing an Anza release schedule published Aug. 13 that said Alpenglow was planned for Sept. 28 through Agave 4.3; the Foundation roadmap does not confirm that date, so September remains unconfirmed. Separately, the slot-time reduction from 400ms toward 200ms proceeds through five gated stages based on acceptable block skip rates before any later stake-weighted supermajority vote on mainnet.