The Stacks PoX-5 Hardfork Upgrade: What to Expect This Week

Stacks activates the PoX-5 hardfork this week, the consensus upgrade that lays the foundation for Bitcoin Staking. Activation happens at Bitcoin block 960,230, expected around 2AM ET on Thursday, July 30. Because activation is tied to a Bitcoin block height, the exact moment shifts as Bitcoin blocks arrive. A live countdown is available on the activation tracker.

Core contributors have completed testing, and the PoX-5 codebase has been audited by Trail of Bits and Clarity Alliance, with additional review by security partner Asymmetric Research. Node software, signers, and miners are ready for the switchover. Miners have upgraded and signers have met the approval threshold required for activation, tracked live on public dashboards. Exchanges have confirmed support for the hardfork and are completing their upgrades . This article covers what the hardfork changes, what STX holders need to do, and what to expect in the hours and days around activation.

What PoX-5 Does

PoX-5 upgrades Proof of Transfer, the Stacks consensus mechanism where miners spend BTC to mine Stacks blocks. In practical terms, the upgrade does three things:

• Introduces Bitcoin Bonds, which let holders pair BTC on Bitcoin L1 with STX on Stacks to earn self-custodial BTC yield without leaving Bitcoin
• Improves the consensus mechanism with functional and quality-of-life updates, including staking without cooldown cycles and streamlined pool participation
• Keeps BTC rewards flowing to STX-only stakers, who continue earning by staking STX alone

Bitcoin Bonds activate at the consensus level on Thursday, July 30th and open for participation in phases. During the bootstrap period, bond capacity is allocated to whitelisted participants, starting with an institutional Genesis Bond expected in late August. Community participation runs through selected staking pools using sBTC as capacity scales. The full design is detailed in the Bitcoin Staking whitepaper.

If You Hold STX

STX balances, wallet addresses, and keys are unaffected. The hardfork creates no new token, requires no swap or migration, and changes nothing about how STX is held. Holders who are not staking do not need to do anything before, during, or after activation.

If You Stake STX: Restaking

Every staker needs to restake to keep earning rewards. The hardfork moves staking from the current contract to the new PoX-5 contract, and following the precedent set by prior PoX upgrades, all currently staked STX unlocks at activation. Restake before block 962,050 to continue earning during the next cycle. Rewards from the final pre-fork cycle pay out normally.

Timing depends on how you stake. Solo stakers can restake directly once PoX-5 is live. Pool participants restake once their pool provider has updated for PoX-5, which can take longer, so check your pool provider's announcements for their reopening schedule.

Restaking also comes with upgrades. PoX-5 removes the cooldown cycle, so stakers can change their reward address without missing a cycle, and streamlines pooled staking so pool participants are less exposed to missed commitments. A step-by-step restaking guide and video walkthrough will be published on Friday.

Why Restake: BTC Rewards Under PoX-5

Restaking keeps you earning. Stakers who re-enroll continue automatically earning BTC yield on Stacks under the new consensus model, exactly as they did before the fork. To earn from the first PoX-5 cycle, complete restaking before the prepare phase of the first post-fork cycle, which starts at Bitcoin block 962,050.

Reward distribution under PoX-5 changes as follows: any bonded BTC positions locked alongside STX receive a fixed target yield first, and everything beyond those obligations splits 85% to STX-only stakers and 15% to a reserve fund that buffers future payouts. The full description of the new waterfall distribution mechanism is detailed in the Bitcoin Staking whitepaper.

PoX-5 also opens a second path further out: Bitcoin Bonds, where holders pair BTC with STX for predictable target yields on their Bitcoin position. Bond capacity is whitelisted during the bootstrap phase, with community access through selected sBTC staking pools, and details follow with the Genesis Bond announcement.

If You Hold STX on an Exchange

Exchanges have confirmed support for the upgrade. Exchanges temporarily pause STX deposits and withdrawals around network upgrades. This is standard procedure for them to handle blockchain hardfork transitions, and it happened during every previous Stacks upgrade. Trading typically continues without interruption, and exchanges handle all technical steps for the STX held on their platforms.

Each exchange sets its own pause window and communicates it through its own announcements. Deposits and withdrawals reopen once each exchange confirms the upgraded network is stable, usually within hours. Anyone planning to move STX on or off an exchange this week should do so before Wednesday 8PM ET.

Around Activation

Block production continues while the network transitions to PoX-5 rules. sBTC deposits and withdrawals continue operating normally through the upgrade. Node operators who have not yet upgraded to stacks-core 4.0.1 must do so before block 960,230 to stay on the network.

Confirmation that the hardfork completed successfully will be posted on official Stacks channels once core contributors have verified the network, with network health data following in the days after.

What Comes Next

PoX-5 activation opens the Bitcoin Staking rollout: restaking under the new contract this week, the institutional Genesis Bond in late August, and bonding capacity scaling through the months after. Every milestone will be announced on official channels as it clears. Stacks is growing Bitcoin, and this week the rails for that get switched on.

Questions and Answers

Is my STX safe during the hardfork?
Yes. Balances, keys, and addresses are unchanged. The upgrade creates no new token and requires no migration.

Do I need to do anything?
Holders who are not staking: no. Stakers: restake once PoX-5 is live, before block 962,050, since all staked STX unlocks at activation.

Why does the hardfork unlock my staked STX?
Staking moves to the new PoX-5 contract. Positions in the old contract cannot carry over automatically, so each staker re-enrolls once, under the new rules. This follows the precedent set by prior PoX upgrades.

When can I restake, and by when?
Solo stakers: once PoX-5 is live. Pool participants: once your pool provider has updated and reopened, so check their announcements. To earn from the first PoX-5 cycle, complete restaking before block 962,050.

Do STX-only stakers still earn BTC under PoX-5?
Yes. After bonded positions receive their target yield, 85% of the remaining miner BTC goes to STX-only stakers and 15% to the reserve fund. With minimal bonded capacity in the first cycles, STX-only stakers receive most of the BTC rewards in this early phase.

What are Bitcoin Bonds?
A new participation path where holders pair BTC with STX to earn self-custodial BTC yield at a target rate. During the bootstrap phase, capacity is allocated to whitelisted participants, beginning with an institutional Genesis Bond expected in late August. Community participation runs through selected staking pools using sBTC, with details at announcement.

Has the PoX-5 code been audited?
Yes. The PoX-5 codebase has been audited by Trail of Bits and Clarity Alliance, with additional review by security partner Asymmetric Research.

Can I trade STX during the upgrade?
Trading typically continues on exchanges. Major exchanges have confirmed support for the hardfork; deposits and withdrawals pause temporarily around activation, so check your exchange's announcement for its exact window.

What happens to rewards from the current staking cycle?
They pay out normally.

Does the hardfork affect sBTC?
No. sBTC operations continue through the upgrade.

What is PoX-5?
The fifth version of Proof of Transfer, upgrading Stacks consensus so the BTC that miners commit can fund structured staking rewards. It is the foundation for self-custodial Bitcoin Staking, detailed in the whitepaper.

When does Bitcoin Staking start?
The rollout begins after activation, starting with an institutional Genesis Bond expected in late August. Details follow on official Stacks channels.

How do I know the network is ready?

Readiness is publicly verifiable. Miners have upgraded and signers have met the approval threshold required for activation, both tracked on live dashboards (miners, signers). The codebase has been audited by Trail of Bits and Clarity Alliance with additional review by Asymmetric Research, and major exchanges have confirmed support. 

‍