Solana turned on Transaction V1 at the start of epoch 1035, on 15 September 2026 at about 01:00 UTC. Our nodes run Agave v4.2.2 and serve v1 blocks, so nothing changes on our side. Your side has one change to make: getBlock and getTransaction calls that still pass "maxSupportedTransactionVersion": 0 now fail with -32015 on almost every block, because almost every block already carries a v1 transaction.
Avalanche's Helicon upgrade activates on 22 September at 15:00 UTC, and our nodes already run the release that carries it. Core shipped an emergency hardfork, Sui moved to protocol 136, and Ethereum mainnet and Sepolia moved to reth v2.5.2. Separately, Solana activated Transaction V1 today, and that one needs a change in your client.
Monad's MONAD_TEN activates on mainnet on 2 September at 14:30 UTC, and our nodes are already on the release that carries it. Sui moved to protocol 135 and Stellar to Protocol 28. On the docs side, the four Agentic RPC pages that moved to a top-level section now answer with a real 301 instead of a page that says 200 and redirects in the browser, and that includes the Markdown twin an agent fetches.
Nine of these upgrades tracked a hard activation, where a node left on the old version stops following the chain. Taiko's Unzen fork and Somnia's Jig fork both activated inside this window and we landed ahead of both. Monad testnet activated MONAD_TEN on 12 August, and our nodes were already on the release that carries it. Nothing changed in RPC method limits, error codes or rate limits.