Bitcoin Core Devs Commit to Changing OP_RETURN Data Storage Limit By October

Bitcoin Core developers have confirmed plans to remove long-standing data storage restrictions in the upcoming version 30 release, scheduled for October 30.

The change essentially eliminates Bitcoin’s current 80-byte limit on OP_RETURN outputs, which are special transaction fields that allow users to embed arbitrary data on the blockchain. Under the new rule, transactions can include multiple OP_RETURN outputs, each potentially containing up to 4MB of data.

“Bitcoin Core is just one protocol implementation that can be copied and modified by anybody; the only thing that makes it special is the way its contributors make decisions,” Gloria Zhao, core contributor to the approved changes, explained in a GitHub note and tweet.

The modification represents a significant policy shift addressing how Bitcoin handles non-financial data.

OP_RETURN outputs, popularized during 2024’s Ordinals inscription boom, allow users to store information like images, text, or metadata directly on Bitcoin’s blockchain without creating spendable outputs that bloat the network’s UTXO (unspent transaction output) database.

It’s worth noting that while users can still manually restore the old 80-byte limit if they prefer, these configuration options will eventually be removed entirely in future Bitcoin Core versions.

The OP_RETURN debate

The confirmation follows months of heated debate among Bitcoiners, with supporters viewing it as a means to enhance Bitcoin into a programmable platform that can support broader use cases, while critics such as longtime Bitcoin Core contributor Jason Hughes argue that the change alters “the nature of what the Bitcoin network itself is in its entirety.”

For Zhao, however, the “primary motivation” behind the decision to implement OP_RETURN was to address people storing data on Bitcoin with harmful methods that permanently bloat the network’s memory—which could represent “a long term cost to the network,” Zhao claimed.

When Bitcoin Core’s rules were stricter than what miners “reliably mined” and accepted, large players started bypassing the public transaction pool and dealing directly with miners. This “creates centralization pressure” and undermines Bitcoin’s design, hurting its censorship resistance, Zhao explained.

By removing OP_RETURN limits, Bitcoin Core aligns its policies with the realities of Bitcoin mining, encouraging people to use the cleaner data storage method instead of forcing them toward either harmful techniques or centralized workarounds.

But Zhao’s attempt at relaying the Bitcoin Core developers’ ideas and motivations for the change was met with backlash from some sections of the Bitcoin community.

“There was no clear consensus on this, and therefore should have been never merged!” Juan David Diaz, a software engineer, commented on the thread.

“This is a disgraceful precedent. There is no consensus for this change,” another commenter using a pseudonym through a newly-made GitHub account wrote.

People apparently don’t understand “that this is by default,” an engineer claiming to work at ZK-enabled Bitcoin infrastructure developer Alpen Labs noted.

“You can still just set your own limits in your config. If you disagree, you can just change it on your nodes,” the pseudonymous engineer claimed.