⚠ DRAFT · BIP 110

REDUCED DATA
TEMPORARY SOFTFORK

A temporary consensus-level softfork to limit arbitrary data storage on Bitcoin — targeting inscriptions, and refocusing the network on its purpose as sound, permissionless money.

Authored by Dathon Ohm · Advised by Luke-Jr

⏳ Time Until Activation

--Days

--Hours

--Minutes

--Seconds

Activation height: 965,664 · Estimated: ~September 2026

STARTED · Miners may signal

📈 Node Adoption — Knots vs Core

Real-time data from reachable listening Bitcoin nodes. Bitcoin Knots implements BIP110; Core (≥30.0) = versions after OP_RETURN limit removal; Core (<30.0) = versions with the traditional OP_RETURN limit.

Total Reachable Nodes

🟠 Bitcoin Knots

🔵 Core ≥30.0 (Post-OP_RETURN)

🟣 Core <30.0 (Pre-OP_RETURN)

Data source: Luke Dashjr's node survey · Core split at v30.0 (OP_RETURN limit removed) · Knots includes all BIP110-signaling variants

? The 5W1H of BIP110

What

A temporary (~1 year) softfork that limits arbitrary data in Bitcoin transactions by restricting scriptPubKeys to ≤34 bytes, witness data pushes to ≤256 bytes, banning OP_IF in Tapscript, and capping Taproot trees to 128 leaves.

Why

To resist data embedding (inscriptions/ordinals) that burdens node operators, distorts fee markets, and diverts development focus away from Bitcoin as money.

Who

Authored by Dathon Ohm with advice from Luke-Jr. Discussion on the bitcoin-dev mailing list.

Where

Enforced at the Bitcoin consensus layer — all full nodes and miners running the softfork validate these rules.

When

Start: Dec 1, 2025 · Activation: ~Sep 2026 · Duration: ~1 year · Expires: ~Sep 2027

How

Modified BIP9 deployment with 55% threshold (vs 95%), mandatory signaling, and automatic expiry.

⚙ The 7 Consensus Rules

Blocks during the temporary deployment are invalid if they violate any of these rules. Pre-activation UTXOs are exempt.

1 New scriptPubKeys exceeding 34 bytes are invalid — except OP_RETURN which allows up to 83 bytes.
2 OP_PUSHDATA* payloads and witness items exceeding 256 bytes are invalid (redeemScripts exempted).
3 Spending undefined witness versions (other than v0, P2TR, P2A) is invalid.
4 Witness stacks containing a Taproot annex are invalid.
5 Taproot control blocks larger than 257 bytes (>128 leaves) are invalid.
6 Tapscripts containing OP_SUCCESS* anywhere are invalid.
7 Tapscripts executing OP_IF or OP_NOTIF are invalid.

📋 Deployment Parameters

Parameter	Value
Name	`reduced_data`
Bit	`4`
Start Time	December 1, 2025
Threshold	55% (vs BIP9 standard 95%)
Max Activation Height	965,664 (~September 1, 2026)
Active Duration	52,416 blocks (~1 year)
Timeout	None (height-based forced lock-in)
Mandatory Signaling	Blocks 961,632 – 963,647

📅 Timeline

2025-12-01

Start Time — Deployment enters STARTED; miners may signal bit 4

~2026-08

Lock-in — 55% reached or forced at height 963,648

~2026-09-01

Activation — Height 965,664. Rules enforced for new UTXOs

~2027-09

Expiry — After 52,416 blocks, rules auto-lift

⚠ Risks & Challenges

🧊 Frozen Funds (Theoretical)

Pre-signed Taproot transactions with OP_IF Tapleaves or trees deeper than 7 levels could become unspendable. Mitigation: 2-week grace period, pre-activation UTXO exemption.

🔧 BitVM & Advanced Contracting

BitVM relies on large Taproot trees (>128 leaves). The 257-byte control block limit may impede mainnet BitVM development during the softfork.

🔗 Miniscript Compatibility

Miniscript compiler may produce OP_IF-based Tapleaves. Needs patching during the deployment.

📉 Low Threshold Controversy

55% miner threshold (vs Bitcoin's standard 95%) is a significant deviation — critics warn of precedent and potential network split risk.

🔄 Upgrade Hooks Disabled

Undefined witness versions and OP_SUCCESS* opcodes are disabled for the deployment's duration.

🎯 Data Storage Arms Race

BIP acknowledges it can't fully prevent spam — but raises cost and sends a clear signal that data storage is unsupported.