With the official rollout of Bitcoin Core v30, adjustments to the relay policy for OP_RETURN have become a central topic of debate within both the Bitcoin community and the mining sector.
According to the published technical notes, the update removes the decade-old 80-byte forwarding limit for OP_RETURN. Under default settings, nodes will now allow a single output to carry nearly 4MB of data. Developers emphasize that this change is strictly at the relay-policy layer and does not modify consensus rules such as block size, but its real impact on mempool structure and on-chain load has already sparked wide discussion.
The network data load has increased by approximately 50,000 times compared to previous levels.
Community Split: Technical Simplification or “Data Overflow”?
Supporters argue that the existing 80-byte limit has long been bypassed in practice through Taproot, witness data, and other methods, which in fact encourage less transparent and more UTXO-unfriendly forms of data embedding. Removing the limit helps unify node behavior, reduce protocol-layer exceptions, and opens more room for applications such as timestamps, cross-chain bridge protocols, and document authentication.
Opponents, however, worry that loosening OP_RETURN will invite a surge of images, text, and other non-financial data into blocks, raising the risk of on-chain “garbage data,” while increasing node storage and verification costs. Over time, they fear this could weaken Bitcoin’s decentralization. Some commentators bluntly claim that Bitcoin is shifting from a “monetary chain” toward a “data chain.”
Price Pullback and Fee Uncertainty: Miners Face Dual Pressure
While protocol-level disputes remain unresolved, the combined effect of high hashrate and elevated difficulty continues to compress miner profit margins. Market expectations suggest that with v30 loosening the OP_RETURN relay policy, large-sized transactions may enter the mempool more easily, intensifying competition for block space. As a result, fee volatility may widen, and miner revenue will rely more heavily on fee contributions.
For large mining farms with stronger capital power and more diversified machine portfolios, rising fees can partially offset the pressure from price pullbacks.
But for small and mid-sized miners who depend on a single machine type or lack electricity-cost advantages, revenue uncertainty only becomes greater.
Block Data Load
The large-scale inflow of so-called “garbage data” onto the chain raises node storage and operational costs by default. Bitcoin full nodes must store and verify the complete blockchain history. When large amounts of non-payment data — images, text, or experimental OP_RETURN payloads — continue to be written into blocks, block size rises steadily, disk requirements expand accordingly, sync times increase, hardware thresholds grow, and the cost of spinning up new nodes rises. Over the long term, this makes “running a full node at home” increasingly difficult. The responsibility of verification gradually shifts toward institutions with high-cost infrastructure, creating structural pressure on Bitcoin’s decentralization and network resilience.
S19 and M60-Below Machines Near Shutdown Price, Miner Reshuffling Accelerates
Under current market prices and electricity costs, parts of the Antminer S19 series are approaching—or have already touched—the shutdown threshold, while Whatsminer M60-and-below models in several regions can no longer cover electricity and maintenance expenses, forcing operators to shut down or dump units into the secondhand market.
Industry analysts point out that under the potentially more congested on-chain environment brought by Bitcoin Core v30, mid- and low-efficiency machines are more sensitive to fee fluctuations and block interval variance. If fees fall in the short term while price fails to recover, these machine types will be the first to be pushed out, further amplifying the “strong-get-stronger” trend among miners.
Protocol Changes Boost Miner Polarization
Based on current technical and market conditions, the boosted impact of Bitcoin Core v30 on miners is mainly reflected in three directions:
- Machine divergence: Newer high-efficiency models gain clear cost and stability advantages, while older generations are forced into an accelerated phase-out.
- Operator concentration: Large-scale miners with low electricity rates, optimized operations, and hedging capability have stronger resilience, driving further concentration of hashrate.
- Revenue structure shift: With block subsidies declining and fee ratios rising, miners must reassess business models built on relying solely on the block subsidy.
Analysts believe that in the short term, miners must recalculate shutdown prices for each model, rebuild cash-flow safety margins, optimize fleet energy efficiency, and secure more competitive electricity and hosting terms. At the industry level, the OP_RETURN controversy and structural miner reshuffling triggered by Bitcoin Core v30 will remain key variables to watch in the Bitcoin ecosystem for some time.
