Qtum

The project began core work in 2016 and made a base-layer choice before mainnet: payments would remain UTXOs, while contracts would see an EVM. AAL sat between them. Instead of asking developers to abandon Solidity or asking node operators to abandon Bitcoin-derived validation, it converted transaction context at the boundary.

That choice made QTUM do several jobs at once. It is the value carried by UTXOs, the gas paid by contracts and the stake competing to make blocks. The design did not make QTUM an Ethereum token; it made Ethereum-style execution a feature of Qtum’s own chain.

At launch, taking part in block production meant keeping coins and a staking node online. Offline staking, activated at block 680,000 on 28 August 2020, let a holder nominate a Super Staker without sending away the coins. The operator did the online work and could charge a share of rewards, while the delegated UTXOs stayed under the holder’s key.

FastLane changed the rhythm eight months later. The April 2021 upgrade cut the target interval from 128 seconds to 32. More frequent blocks also meant the protocol had to preserve its delayed reward and maturity rules rather than treating speed as free capacity. Qtum changed participation and timing while keeping the original UTXO stake model.

The architecture’s bill arrived as Bitcoin Core and Ethereum evolved. In September 2023, v24.1 combined Bitcoin Core 24.1 changes with EVM Shanghai. Later mandatory releases brought Dencun and then Bitcoin Core 27–29 plus selected Pectra functionality. DGP could tune block and gas parameters, but it could not substitute for these releases; node operators still had to install consensus-compatible software.

The chain’s monetary clock kept moving too. The second halving on 30 November 2025 lowered the subsidy from 0.5 to 0.25 QTUM. The Foundation later dated v29.1 activation to 11 January 2026, while the release notice had forecast block 5,483,000 for 12 January UTC. v30.2 refreshed the Bitcoin-derived base again in July without a hard fork label. Qtum’s durability is therefore measured less by the original phrase ‘Bitcoin plus Ethereum’ than by whether maintainers and stakers can keep reconciling both lineages.

Qtum Foundation’s own retrospective says leaving China in 2019 disrupted the project and that expensive outside management and partnership-led plans failed to produce enough. In 2024 it put older core-team members back into development and decision-making. The next wave of releases followed that change in direction. The sources do not by themselves prove that the personnel change caused the faster cadence, but they do show that responsibility for setting priorities moved back toward the original team.

The same retrospective mixed shipped core releases with bridge, stablecoin and AI plans. That makes status discipline part of reading Qtum. Activated hard forks, official release records and published binary hashes are chain history; a product assigned a season or waiting for an external directory remains a promise. The next chapter depends on which of those plans reaches mainnet without distracting from the two-codebase maintenance job.