Bitcoin Core Lowers Default Minimum Relay Fee
Bitcoin’s core software has officially reduced the default minimum relay fee for transactions, representing one of the most notable changes in recent years regarding the cost of transferring funds across the network.
Bitcoin Core 29.1, which was released on Sept. 4, sets the new default minimum relay fee rate to 100 satoshis per thousand virtual bytes (0.1 sats/vB), a substantial 90% decrease from the earlier default rate of 1 sat/vB. Users incur fees calculated in satoshis (the smallest Bitcoin unit) multiplied by the size of their transactions.
Although each individual node operator has the ability to modify this setting, it is anticipated that most will retain the default value. Nodes typically do not relay and often disregard transactions with fees that fall below the minimum relay fee rate they have set.
The change was decided by Bitcoin Core developers on Aug. 15, motivated by “bitcoin’s exchange rate changes in the last ~10 years.” The proposal indicated that the minimum fee serves as a denial-of-service (DoS) attack protection measure, but suggested that, given the significantly higher prices now, a lower fee in Bitcoin (BTC) is acceptable.
Data from BitRef shows that over 72.5% of all Bitcoin nodes (18,811) are running the Bitcoin Core node software, while nearly 27.25% operate Bitcoin Knots, a fork of the Bitcoin Core software designed to enhance user control. A deeper analysis revealed that the most widely used node software is Bitcoin Core 29, with 4,510 nodes representing over 18% of the network.
- 3,991 Bitcoin Core 28.1 nodes (almost 16%)
- 3,083 Bitcoin Knots 29.1 nodes (12.31%)
- Only 571 nodes operating Bitcoin Core 29.1, making up less than 2.3% of the network
Although Bitcoin Knots 29.1 is derived from Bitcoin Core 29.1, it does not adopt its new defaults. Instead, with this update, Knots chose to “make most policy options configurable in GUI Options, and add ‘corepolicy’ option to use Bitcoin Core defaults.”
A significant number of the 571 Bitcoin nodes running Bitcoin Core 29.1, along with an unpredictable portion of the 3,083 Bitcoin Knots 29.1 nodes, are likely implementing the newer, lower minimum relay fee policy.
Gloria Zhao, a Bitcoin Core developer, mentioned that this change also stems from a recent trend where transactions falling below the previous limit are mined regardless. This is due to the fact that although the default value was set in a specific manner, node operators could apply their preferred values.
More Read
This situation led to complications, as “blocks with lots of sub-1sat/vB transactions don’t propagate as quickly to nodes that rejected or didn’t hear about those transactions earlier.” Nevertheless, to maintain the network’s defenses against spam and DoS attacks, Zhao emphasized the importance of not setting the default value too low, while still reducing it to avert the aforementioned block relay problems.
The Bitcoin network data service Mempool.Space also supported the initiative for lower fees, encouraging users not to overpay for blockchain space. “0.1 sat/vB is the new one sat/vB,” it stated in a mid-July X post.
