The Bitcoin Core development team has officially released version 30.0, a major upgrade that retires earlier versions (27.x and older) and introduces sweeping changes to node architecture, performance, and policy.
In their announcement, the maintainers state that legacy clients will no longer receive updates, emphasizing the significance of the shift.
Perhaps the most controversial change is the massive increase in the OP_RETURN data limit.
Previously capped at 80 bytes, the new default is elevated to 100,000 bytes, and multiple OP_RETURN outputs are now allowed in a single transaction,effectively bringing data embedding closer to being constrained only by transaction size or block weight limits.
Node operators who wish to maintain the older limit can override the default by setting. Supporters of the change argue that it aligns Bitcoin Core’s default policies more closely with what miners already accept, promotes neutrality in the fee market, and reduces the incentive to rely on harder-to-prune data embedding methods.
They point out that OP_RETURN outputs are prunable and do not burden the UTXO set, and claim that enlarging the permissible payload can support more advanced on‑chain applications.
But critics warn of serious risks. Purists argue that allowing large non‑financial data opens the door for spam, bloat, and worse,embedding illicit or objectionable content into the blockchain that every full node must relay or store.
Some voices caution of existential threats, one group warns that hosted nodes might be forced offline by malware detection filters due to large payloads, triggering cascading failures.
Others fear the move erodes trust in Bitcoin Core’s governance and could push more operators toward alternative clients like Bitcoin Knots.
Beyond OP_RETURN, v30 also tightens DoS limits in the transaction orphanage subsystem, improves P2P package relay for common parent‑child topologies, and updates fee‑rate behavior and wallet tools.
The version is now live for users to download and test. With node policy, censorship resistance, and client diversity at stake, Bitcoin is witnessing a renewed fault line, whether to favor maximal neutrality and extensibility, or to preserve minimalism and guardrails against abuse.