Solana, Ethereum, Avalanche and Bitcoin diverge on upgrade priorities

• —Solana's Alpenglow (Votor) aims to cut finality from ~12.8 seconds to ~150 ms, shipping in Agave 4.3 in October 2026
• —Ethereum's Hegotá (EIP-8141, EIP-7805) builds a base for privacy-preserving and quantum-resistant signatures, mainnet targeted for Q2 2027
• —Avalanche activated Helicon on Sept 23: validator minimum stake period cut from 2 weeks to 48 hours, uptime threshold raised from 80% to 90%
• —Researchers at [alloc] init proposed Shielded Bitcoin, using ZK proofs and OP_RETURN to hide amounts and addresses without changing BTC consensus