BIP‑110 faces possible self‑fork or activation failure by August 7

Bitcoin developer Adam Back has warned that the contentious BIP‑110 proposal could either cause a self‑fork around August 7, 2026, or simply never activate due to lack of support [1]. The change, which would sharply restrict arbitrary data stored in Bitcoin transactions, has attracted virtually no backing from mining pools and only a small fraction of node operators.

Key takeaways

• BIP‑110 would cap OP_RETURN data at 83 bytes and limit data pushes to 256 bytes, affecting protocols such as Ordinals and Runes [1].
• Node support sits between 2.4 % and 4.5 % as of March 2026, mainly from the Bitcoin Knots implementation [1].
• No major mining pool has signaled support for the proposal, leaving activation odds low [1].
• The mandatory enforcement block is height 961,632, expected around 17:59 UTC on August 7, 2026 [1].
• Back describes the change as an “intentional literal downgrade” that could freeze UTXOs and cause a chain split if a minority of nodes enforce it [1].

BIP‑110’s technical aims and activation path

BIP‑110, originally introduced as BIP‑444 in late 2025 before being renumbered, seeks to impose strict limits on non‑monetary data in Bitcoin transactions. By capping OP_RETURN outputs at 83 bytes and restricting arbitrary data pushes to 256 bytes, the proposal would make it significantly harder for on‑chain metadata projects such as Ordinals and Runes to embed images, tokens, and other data in block space [1]. The change is structured as a one‑year soft fork, but it relies on a User‑Activated Soft Fork (UASF) mechanism: nodes that run compatible software would begin enforcing the rules regardless of miner consensus once the activation block height is reached. This approach mirrors the 2017 SegWit activation, though Back notes that the current proposal lacks the broad community backing that SegWit enjoyed [1].

Support for the UASF is minimal. As of March 2026, only about 2.4 %–4.5 % of network nodes signal readiness, with most of that support coming from the Bitcoin Knots client maintained by Luke Dashjr, a vocal advocate for limiting non‑monetary data [1]. No major mining pools have signaled any intention to adopt the change, leaving the activation threshold effectively unmet [1]. The enforcement block—height 961,632—is projected to occur around August 7, 2026, at roughly 17:59 UTC, at which point any node running BIP‑110‑compatible software would reject blocks that violate the new limits [1].

Risks of a self‑fork and the broader debate

If a small group of nodes enforces BIP‑110 at the activation height while the rest of the network continues to accept the existing rules, a chain split could occur. Back warns that such a split would create confusion and volatility, potentially locking up Bitcoin held in outputs that become unspendable under the new restrictions [1]. Jameson Lopp, another prominent Bitcoin developer, has echoed concerns that the proposal could break compatibility with existing scripts and protocols, further heightening the risk of a fragmented ecosystem [1].