Spec 420 Is on Testnet. Here Is What Changes for TAO Holders

A new Bittensor protocol upgrade called Spec 420 is running on testnet right now, and it carries three separate changes that touch how subnet markets price, trade, and reach consensus, as laid out in @2xnmore’s thread on X.

The upgrade replaces the liquidity engine underneath every subnet alpha token, adds the trading tools that serious capital treats as a prerequisite, and hands subnet owners direct control over their consensus clock. None of that shows up on a price chart, which is why most holders scrolling TAO’s weekly move have missed it entirely.

For anyone running a subnet, mining, validating, or holding meaningful alpha, this is the upgrade worth understanding before it reaches mainnet.

The AMM beneath every subnet token gets replaced

The largest structural change in Spec 420 is the removal of Uniswap V3 as the liquidity layer for subnet pools, a role it has held since dTAO launched.

In its place comes PalSwap, a weighted balancer-style automated market maker built natively into the protocol rather than bolted on top. The two models distribute liquidity in very different ways, and that difference is the entire point.

• Uniswap V3 (concentrated liquidity): providers pick narrow price ranges where their capital is active, which is highly capital-efficient inside the range but produces thin order books and sharp price cliffs the moment price moves outside it.
• PalSwap (weighted AMM): liquidity is spread across the pool by configurable weights, giving smoother price discovery, more consistent depth across a wider range, and far less exposure to cliff-edge moves.

This is not a cosmetic detail, because the emission formula that went live with the price-based emissions upgrade (Spec 421) uses each subnet’s alpha EMA price as a direct input.

The daily emission share for a subnet is calculated as root_proportion × EMA price × (1 − miner burn), so a distorted or thin price signal produces a distorted emission allocation.

Alpha tokens swing hard during emissions cycles, validator weight changes, and new subnet launches, and concentrated-liquidity cliffs turn that volatility into price moves that do not reflect real changes in subnet value.

A more reliable and harder-to-manipulate price signal is a precondition for the incentive mechanism to allocate honestly.

Advanced limit orders come to on-chain trading

On-chain trading of subnet alpha has been fairly primitive so far, limited to market orders and basic swaps. Spec 420 introduces a new pallet for advanced limit orders on TAO and alpha token swaps, which lets you specify the exact price at which you want to buy or sell while the order rests on chain until it fills or you cancel it. That opens up trading behavior that was not previously possible directly on the Bittensor chain.

• Miners and validators can accumulate subnet positions at set prices instead of market-buying and immediately moving the EMA price that feeds their own subnet’s emission share.
• Subnet owners can manage their alpha token price with precision rather than relying on blunt market operations.
• Institutional and sophisticated traders who treat limit orders as a baseline before touching any market now have an on-chain path into subnet alpha exposure that did not exist before.

The participants who move serious capital into alpha positions generally will not do it without this tooling in place, and Spec 420 removes that barrier.

Subnet owners get control of the consensus clock

Every subnet currently runs on a fixed tempo, a predetermined block interval between Yuma Consensus epochs. The epoch is the moment the network calculates validator scores, updates miner weights, and distributes emissions, and until now that schedule has been locked to the network default. Spec 420 gives subnet owners two capabilities that change how they can operate.

• Configurable tempo: owners set a custom tempo for their own subnet instead of the network default. A high-frequency inference subnet that needs rapid feedback can shorten its tempo to update weights more often, while a long-duration training subnet can lengthen it so validators have enough time to score miner output before the epoch runs.
• Manually triggered epochs: owners can fire an epoch outside the normal schedule when something material happens inside the subnet, such as a new model architecture, a significant miner joining or leaving, or a critical parameter update, rather than waiting for the next scheduled epoch.

Every subnet on Bittensor is a different market producing a different commodity, and forcing all of them onto one consensus clock creates mismatches between how fast a subnet works and how fast it gets scored. Tempo control lets validator scoring and emission allocation track what is actually happening inside each subnet.

What to watch before mainnet

The three changes look separate but push in one direction, since a reliable price signal, mature trading tools, and tunable consensus all reduce the friction that has kept subnet markets from working cleanly at scale.

PalSwap steadies the price that feeds emissions, limit orders let larger participants trade without distorting that same signal, and tempo control lets scoring match the real cadence of work inside each subnet.

Spec 420 currently sits on testnet, the pull request is merged into Subtensor, and the official docs list its status as active, with the timeline to mainnet depending on confirmed stability under real network conditions.

Once it ships, the AMM change alone will reprice every subnet alpha token from day one, which makes this the upgrade to track for anyone running, mining, validating, or holding alpha.

Read more below:

Bittensor’s Spec 420 Rebuilds How dTAO Markets Price, Trade and Reach Consensus