Solana Validators Without a BLS Key Are Already Out of Consensus. That Is Not Alpenglow.
Solana's VAT feature has excluded validators without a registered BLS pubkey from consensus since July 22, 2026. The Foundation says that gate is not Alpenglow.
Solana validators without a registered BLS public key have been excluded from consensus since July 22, 2026. The Solana Foundation says that exclusion is Validator Admission Ticket enforcement, not Alpenglow going live.
BLS keys are a cryptographic prerequisite for the future Alpenglow consensus switch. The Validator Admission Ticket, VAT, checks that those keys exist and caps the admitted set. TowerBFT remains the live consensus protocol.
Who, what, when, and where
The Solana Foundation lists two related feature gates as live on mainnet.
SIMD-0387, BLS pubkey management in the vote account, activated on mainnet on July 8, 2026. The feature gate address is AnAP9zPV4KL7czAPQbFhpDKV2tx7g4UGNbK9wvXwjaRo.
SIMD-0357, the Validator Admission Ticket, activated on mainnet on July 22, 2026. The feature gate address is VAT9huvhPjRN9cyrPytq9rwvEJ3J4ADtjdncgZRyANJ.
The Foundation BLS pubkey and VAT page says both features are also active on devnet and testnet. Registering a BLS pubkey requires Solana CLI 4.1.0 or higher. Anza documents the command flow in its vote-account guide.
Confirmed evidence
According to the Foundation page, validators without a registered BLS pubkey are excluded from the admitted set, stop voting, do not participate in consensus, and stop earning inflation rewards. Validators with a BLS pubkey but outside the top 2,000 by stake are excluded from the admitted set for that epoch. The page labels this a breaking change.
The same page states that VAT feature activation does not turn on Alpenglow itself. VAT gates admission based on the existence of the BLS pubkey. The consensus switch is a separate change, SIMD-0326, expected with Agave 4.3.
Context and timeline
Before Alpenglow, TowerBFT remains in effect. Votes remain on-chain transactions. The Foundation page says voting validators continue to be charged about 2 SOL per epoch in aggregate voting costs.
After Alpenglow is enabled, the same page says every voting validator included for the next epoch is charged a flat 1.6 SOL fee per epoch, burned from the vote account to the incinerator. Votes will no longer be on-chain transactions.
The Foundation page explains why Alpenglow needs BLS keys: Votor combines many validator votes into one aggregate certificate. Ed25519 signatures, used for current voting, do not support that aggregation.
Foundation pages disagree on Alpenglow timing. The BLS/VAT page says SIMD-0326 will be activated once Agave 4.3 is on mainnet, expected in Q4 2026. The Alpenglow page lists expected mainnet activation as Q3 2026 and marks the upgrade In Development. The upgrades index lists Agave 4.3 as planned, expected October 2026. This report does not choose among those dates.
The Alpenglow page states a target of roughly 150ms finality. That figure is a Foundation target for the future protocol, not a live mainnet measurement.
What remains unknown
- How many mainnet validators currently lack a registered BLS pubkey. Foundation pages do not publish that count.
- Which published Alpenglow timing will hold.
- When Agave 4.3 actually reaches mainnet.
What to watch next
Track feature gates AnAP9zPV4KL7czAPQbFhpDKV2tx7g4UGNbK9wvXwjaRo and VAT9huvhPjRN9cyrPytq9rwvEJ3J4ADtjdncgZRyANJ.
Compare the BLS/VAT page and the Alpenglow page for status changes. Watch the Agave 4.3 listing on the upgrades index. Check Anza's vote-account guide for the current registration commands.
Sources and disclosures
- https://solana.com/upgrades/bls-pubkey-vat: Official BLS pubkey and VAT page, live status, dates, and admission rules. Updated July 2026.
- https://github.com/solana-foundation/solana-improvement-documents/blob/main/proposals/0387-bls-pubkey-management-in-vote-account.md: SIMD-0387 proposal.
- https://github.com/solana-foundation/solana-improvement-documents/blob/main/proposals/0357-alpenglow_validator_admission_ticket.md: SIMD-0357 proposal.
- https://explorer.solana.com/address/AnAP9zPV4KL7czAPQbFhpDKV2tx7g4UGNbK9wvXwjaRo/feature-gate?cluster=mainnet-beta: BLS pubkey feature gate.
- https://explorer.solana.com/address/VAT9huvhPjRN9cyrPytq9rwvEJ3J4ADtjdncgZRyANJ/feature-gate?cluster=mainnet-beta: VAT feature gate.
- https://docs.anza.xyz/operations/guides/vote-accounts#set-the-bls-public-key: Anza vote-account guide for BLS registration.
- https://solana.com/upgrades/alpenglow: Alpenglow page, still In Development, Q3 2026 expected date.
- https://solana.com/upgrades: Upgrades index listing Agave 4.3 as planned, expected October 2026.
This article is independent editorial coverage of Solana's live BLS pubkey and validator admission ticket rules, based on the cited Foundation pages, SIMD documents, explorer feature gates, and Anza vote-account guide as they stood on the dates given. It is not investment, financial, legal, tax, or security advice, and it is not validator-operations or technical implementation advice. Operators should use official Anza commands, Solana documentation, or qualified professional guidance.