Agave 4.0: XDP Turbine, QUIC-only TPU and P-Token in the mainnet upgrade candidate
Anza published the Agave 4.0 patch notes: XDP for Turbine cuts retransmit from around 600 ms to about 0.8 ms, QUIC becomes the only TPU path, plus async verification and P-Token activation. Full mainnet rollout targeted for May 2026.
What happened
Anza published the Agave 4.0 patch notes. According to Anza, Agave 4.0 is a mainnet upgrade candidate and targets a full mainnet rollout in May 2026. Anza states that validators and developers should “begin testing with Agave 4.0 on testnet and prepare for the mainnet rollout”. Source: Agave 4.0 patch notes.
What Agave 4.0 changes
- XDP for Turbine: Turbine retransmit drops, per Anza, from around 600 ms to about 0.8 ms, accelerated via eBPF programs at the network interface (XDP).
- QUIC-only TPU: UDP transaction ingestion is removed. From Agave 4.0, QUIC is the only way to submit transactions to a validator. The flags
--public-tpu-addressand--public-tpu-forwards-addressnow address QUIC ports exclusively. - Async verification: PoH entry verification runs asynchronously, Ed25519 signature checks run in the background and are joined before the block is accepted. This moves expensive operations off the critical replay path.
- P-Token activation: during the 4.0 cycle the P-Token program is activated — a drop-in replacement for the SPL Token program. Anza estimates this frees roughly 12 percent of block capacity network-wide.
What P-Token is
P-Token is a re-implemented, compute-optimized version of the SPL Token program at the same program address. Technical specification: SIMD-0266 “Efficient Token Program”.
What to watch next
- When Anza moves Agave 4.0 from upgrade candidate to a mainnet recommendation.
- How removing the UDP TPU affects transaction senders that do not yet use QUIC.
- Whether the estimated roughly 12 percent of freed block capacity is confirmed network-wide after P-Token activation.
Not financial advice. This article describes a technical validator-client release.