Flux v9.1.0 — C++20 Upgrade, Boost Removal & Performance Improvements

Release Overview

The v9.1.0 release is a major modernization release that upgrades fluxd to C++20 and completely removes the Boost dependency, alongside meaningful performance improvements, BIP 152 Compact Blocks support, ZMQ real-time events, and several p2p networking and fluxnode robustness fixes.

Highlights

• C++20 Upgrade & Boost Removal: Completed across 9 phases — fluxd no longer depends on Boost (#278, #279)
• OpenSSL Upgrade: 1.1.1a → 3.5.4 LTS
• BIP 152 — Compact Headers & Compact Blocks: Faster block propagation (#266)
• IBD Speedups: Initial Block Download performance improvements (#277)
• ZMQ Real-time Events: New realtime event stream over ZMQ (#273)
• Batched Fluxnode DB Writes: Reduced disk I/O on fluxnode state updates (#269)
• P2P Network Resilience: Ported Bitcoin Core fixes to prevent p2p stalls (#274)
• New RPC: listfluxnodedelegates (#271)
• Improved Delegate Startup (#270)
• Robustness Improvements: Enhanced fluxnode block signature checks, emergency checks, and fluxnode p2p transaction handling
• Bug Fixes:
  • Detect corrupt block index entries during load (#276)
  • Null-terminate readlink buffer before dirname call (#275)
  • Write to disk on next block after tip disconnected (#244)

Read more about v9.0.0 release here https://github.com/RunOnFlux/fluxd/releases/tag/v9.0.0

Whitepaper of PoUW v2

https://fluxdrive.runonflux.io/ipfs/QmW3TNPx5Ru3u3UhXf8GqyVNS3avSsttqjamhF395qe17M

How to Upgrade

Automatic Updates

If you're running a Flux node with automatic updates enabled, this release will be deployed automatically according to your update schedule.

Manual Installation

From Binary Releases:

1. Download the appropriate binary for your platform from the GitHub releases page
2. Stop your current Flux daemon: flux-cli stop
3. Replace the old binaries with the new ones
4. Restart your Flux daemon: ./fluxd -daemon

From Debian Package:

# Download and install the .deb package for your architecture
wget https://github.com/RunOnFlux/fluxd/releases/download/v9.1.0/flux-amd64-v9.1.0.deb
sudo dpkg -i flux-amd64-9.1.0.deb

Building from Source:

git clone https://github.com/RunOnFlux/fluxd.git
cd fluxd
git checkout v9.1.0
./zcutil/build.sh

Using APT:

• Follow instructions on https://apt.runonflux.io

CDN, Bootstrap:

• https://cdn.runonflux.io/fluxd

Full Changelog: v9.0.6...v9.1.0