Jito Details BAM's Alpenglow Plan: Maintenance Mode for All Mainnet Nodes, No FireBAM During the Transition

Jito JTO$0.541+5.3% plans to place every mainnet node of BAM (Block Assembly Marketplace) into what it calls Maintenance Mode in the days before the Alpenglow upgrade activates on Solana SOL$109.94+0.2% mainnet, and it has told validators running FireBAM, the Firedancer-based BAM client, to move to an Agave-based build for the transition. The instructions lead the BAM changelog published on 9 October 2026 under the heading "Action Required", and Jito's X account posted a linked article two minutes after the changelog went live.

BAM nodes order transactions and bundles and pass them to the validator producing the block. The changelog says BAM secures 164 million SOL across 385 connected validators, 37% of total network stake as of epoch 1050. Solana Compass epoch data puts active stake in epoch 1050 at 442.9 million SOL, which matches that share. FireBAM accounts for 7.3 million SOL across 12 validators, 4.6% of BAM stake, according to the same post.

The post asks nothing of people staking with a BAM-connected validator. Each operator's stake and performance is on our validator pages.

What BAM Maintenance Mode switches off: MPP and Direct Bundle Ingest

While BAM nodes are in Maintenance Mode, connected validators "revert to ordinary Jito-Agave Block Engine mode", the changelog says. Validators keep producing blocks and keep accepting bundles through the Block Engine, the Jito bundle service that predates BAM. Two BAM-only features are unavailable for the duration: the Maker Priority Plugin (MPP), which on-chain market makers use to send price updates, and Direct Bundle Ingest (DBI), a bundle-submission path into BAM.

Jito tells MPP users to submit oracle updates through TPU, the validator's standard transaction intake, or through the Block Engine, and tells DBI users to fall back to the legacy Block Engine bundle path. Validators, FullSend users and standard bundle senders have no action to take. The changelog says proprietary AMMs route roughly 80% of their updates through MPP, so those market makers have the most to change.

After activation, BAM nodes "are brought back online gradually while performance is monitored". Jito first set out the plan in a 5 October 2026 post on BAM readiness, which says BAM was tested on testnet and on the dedicated Alpenglow test cluster.

FireBAM is not Alpenglow-ready, and Jito-Solana version guidance is mixed

The firmest instruction is for FireBAM and FrankenBAM operators: do not run either during the Alpenglow transition. Jito writes that version 26.09 "is not Alpenglow-ready" and that operators should use 26.10 or later after activation. The changelog still lists FireBAM v26.09.5 as the minimum and recommended mainnet release, so those 12 validators have to change clients for the transition and need 26.10 or later before returning to FireBAM. Jito also warns that a production validator built with dev-context-only-utils "will be forked off during activation".

For the Agave-based client, the 9 October post points in two directions. Its heading and its release list name Jito-Solana v4.3.0-jito.0, released on 2 October, as the mainnet build to run. Its action list links v4.3.0-jito.1 as the release Jito "currently" recommends, and names that build as the one FireBAM operators should switch to. GitHub lists v4.3.0-jito.1 as a pre-release published on 8 October whose notes include "support Alpenglow-aware transaction and bundle buffering".

Jito says it will confirm the minimum supported version before activation, and that Anza and the Solana Foundation "have not yet specified the mainnet transition version". The confirmed number is due in Jito's Discord validator announcements.

Activation epoch still unconfirmed as Jito's auction cadence tightens to 20ms

No activation epoch has been confirmed for Alpenglow, the replacement for Solana's consensus protocol. Jito describes mainnet activation as "approaching in mid-October (per latest Solana Foundation / Anza information)" and says the activation epoch, maintenance timing and restoration updates will be published on Discord. Until then, the maintenance window has no start date and no stated length beyond "the days leading up to activation". RPC and indexing users have their own checklist, which we covered in Triton One's Alpenglow integrator guide.

One BAM change has already taken effect. Solana's 200ms slot time went live at epoch 1053 on 9 October, and the changelog says BAM's auction cadence is derived from slot length, so rounds tighten from 25ms to 20ms with no configuration change required.