Solana's upgrade roadmap advanced on two fronts in August: testnet reached 300ms block times on August 10 ahead of Agave 4.2 feature activations on mainnet-beta starting August 17, and Anza published a tentative Agave 4.3 schedule on August 12 targeting September 28 for Alpenglow consensus activation. Agave 4.2 introduces staged slot-time reductions under SIMD-0525, raises the transaction size cap from 1,232 bytes to 4,096 bytes, and cuts rent-related storage costs by 90%, while Agave 4.3 is slated to switch on Alpenglow, add SHA512 and big-integer modular exponentiation syscalls, and deepen the CPI limit. The v4.3 timeline drew added focus after a same-day Teraswitch routing failure pushed 28.83% of staked SOL offline, still below the one-third threshold that would halt finality under Tower BFT; Solana co-founder Anatoly Yakovenko said Alpenglow can survive "to 40% down." Validators must register a BLS public key on-chain before Alpenglow activation or they will be excluded from the new consensus set, and Anza said all v4.3 dates may change.