Bitlight Bitcoin Infrastructure Modernization

Bitcoin Core v31.0 & Cluster Mempool Upgrade

Overview of Changes

Upgrade Date: 2026-05-22

1. Bitcoin Core v28 → v31.0

1.1 Cluster Mempool (Comprehensive Mempool Architecture Refactor)

The mempool architecture has been refactored from the traditional "per-transaction independent tracking" model into a * Cluster Mempool* design:

• Transactions are ordered by expected mining profitability using chunk feerate evaluation, improving block template construction
• RBF policy has been upgraded: replacement transactions must make the mempool feerate diagram strictly better, eliminating known pathological replacement scenarios
• Ancestor/descendant count limits have been removed and replaced with cluster-based limits:
  • Maximum 64 transactions
  • Maximum 101 kB total cluster size
• New RPC methods:
  • getmempoolcluster: returns the cluster membership and ordering of a transaction
  • getmempoolfeeratediagram: returns the global mempool feerate diagram

Value for RGB Layer2 protocols:

• More predictable CPFP / RBF behavior
• More stable fee competition mechanics for on-chain contract settlement and commitment transactions

1.2 Improved Fee Estimator Precision

The minimum fee-rate tracking bucket has been reduced from 1 sat/vB to 0.1 sat/vB, aligning with the node's minrelaytxfee.

This significantly improves fee estimation accuracy in low-fee environments and reduces unnecessary overpayment caused by conservative fee estimation.

1.3 Increased Default dbcache Size (Validation & Indexing Performance Improvements)

When ≥4 GB RAM is detected, the default -dbcache value is increased from 450 MB to 1024 MB, substantially improving:

• Initial block download (IBD)
• Chainstate validation
• General synchronization performance

1.4 Private Broadcast

sendrawtransaction now supports the -privatebroadcast option, enabling transaction relay through Tor / I2P to improve privacy by reducing:

• Originating IP leakage
• Transaction-to-peer correlation

2. mempool-electrs Upgrade (v3.3.0)

2.1 Mempool Backend API

The mempool.space backend service has been deployed, extending the legacy electrs API with dedicated mempool endpoints:

• Multi-tier fee estimation:
  • fastest
  • halfHour
  • hour
  • economy
  • minimum
• Fee estimation precision improved from 1 sat/vB to 0.1 sat/vB

Current Status: Infrastructure deployment completed; Wallet integration is in progress.

Future versions will prioritize this API for:

• Transaction fee selection
• Protocol settlement workflows

2.2 Electrs API Compatibility

Existing electrs endpoints remain unchanged, enabling seamless migration for:

• BTC Wallet Store
• RGB-related services

with no application-layer modifications required.

References

• Bitcoin Core v31.0 Release Notes (opens in a new tab)
• Cluster Mempool Proposal (Delving Bitcoin) (opens in a new tab)