# QRL Legacy vs QRL 2.0

> A side-by-side guide to QRL's two chains — what's the same, what's different, and how they relate.

QRL is two chains running in parallel: **QRL Legacy** and **QRL 2.0**. They share a goal — quantum-resistant cryptography — but differ in almost every mechanism. This guide lays them side by side.

## The one-line summary

- **[QRL Legacy](/learn/glossary#qrl-legacy)** — the original chain (2018), mined, hash-based signatures, no smart contracts. Becoming a read-only archive.
- **[QRL 2.0](/learn/glossary#qrl2)** — the successor, staked, lattice signatures, EVM smart contracts. The future home of the project.

They're two stages of **one project**, not competitors.

## Side by side

| | QRL Legacy | QRL 2.0 |
|---|---|---|
| Status | Original mainnet → read-only archive | Current + future main chain |
| Consensus | [Proof-of-Work](/learn/consensus-pow-vs-pos) (mining) | [Proof-of-Stake](/learn/proof-of-stake-on-qrl2) (staking) |
| Signature | [XMSS](/learn/xmss-explained) (hash-based, stateful) | [ML-DSA-87](/learn/ml-dsa-87-explained) (lattice, stateless) |
| Smart contracts | No (fixed transaction types) | [Yes (EVM-compatible)](/learn/smart-contracts-on-qrl2) |
| Address length | 79 characters | 41 characters |
| Mining algorithm | [QRandomX](/learn/qrandomx-mining) | — (not mined) |
| Reward mechanism | Mined block reward | Validator [withdrawals](/learn/withdrawals-explained) |
| RPC style | gRPC | JSON-RPC (`qrl_*`) |

## What's the same

Despite all those differences, the core identity holds across both chains:

- **Quantum resistance.** Both sign with post-quantum schemes — there's no quantum-vulnerable window on either.
- **The `Q` prefix.** Both write addresses starting with `Q` (tell them apart by [length](/learn/qrl-address-formats)).
- **One project.** QRL 2.0 succeeds QRL Legacy; they're not separate ecosystems.

## How they relate

QRL 2.0 is the **successor** to QRL Legacy. The plan is for value to move from the old chain to the new one through a [migration](/learn/the-qrl-migration), after which QRL Legacy settles into the role of a **permanent, read-only archive** — its full history stays viewable here, but new activity happens on QRL 2.0.

Importantly, Legacy is **not deleted or sunset**. Anyone who wants to trace the project's history, or verify old balances, can always do so. The explorer keeps both chains first-class for exactly this reason.

## How Quantascan presents them

This explorer treats the two chains separately and honestly:

- QRL 2.0 lives at the bare URLs (`/blocks`, `/address/…`); QRL Legacy lives under a `/qrl-legacy/` prefix.
- A chain switcher in the header flips between them.
- Cross-chain views (like the [richlist](/learn/understanding-the-richlist) and [supply](/learn/qrl-tokenomics-and-supply)) combine both while always keeping track of which chain each figure belongs to.

## Where to go next

- [The QRL → QRL 2.0 migration](/learn/the-qrl-migration) — how value moves between them.
- [QRL address formats](/learn/qrl-address-formats) — the 79- vs 41-character split.
- [Proof-of-Work vs Proof-of-Stake](/learn/consensus-pow-vs-pos) — the consensus difference.