The next meetup will again be held in the building of Germany’s oldest private bank. We’ll meet for a relaxed get-together, exchange of ideas and discussions in the Bistro Massif Central.

• Open Street Maps
• Google Maps
• Koordinaten: 50.110097 8.679097

We’ll meet at the Gibson Wintermarket. They accept Bitcoin payments!

• Google Maps

We’ll meet at the Gibson Wintermarket. They accept Bitcoin payments!

• Google Maps

We’ll host the fourth FFM Socratic Seminar.

These rules exist so that BitDevs participants can speak freely within the event:

• No photos, videos, or recordings.
• Chatham House Rule: you may reiterate the contents of the meeting without attribution.

Topics:

Security / CVEs / InfoSec / Research

• Unstoppable JPGs In Private Keys (E)
• New miner from Block called Proto Rig has obvious problems (E)
• Anatomy of a Billion-Download NPM Supply-Chain Attack (E)
• Infiltrated Selfish Mining (E)
• Bitcoin Core Code: C++, some Python and a Custom Build System (E)
• EPrint: 2025/1001 (F)

Legal (F)

• Samourai Wallet developers plead guilty (F)
• Tornado Cash trial concludes: Roman Storm found guilty of one of three counts (F)
• Oberlandesgericht: Virtuelle Entwendung von Kryptowerten bleibt straflos (F)

Network Data

• ASMap not blocking Knots nodes (F)
• Antoine: Misbehaving nodes (F)
• Sankey Merkle Branches Visualization (E)

Miscellaneous

• Block filter design guide (E)

Delving Bitcoin

• The state of Bitcoinfuzz (E)
• Eclipsing Bitcoin Nodes with BGP Interception Attacks (F)
• Sharing block templates (F)
• Measuring minrelaytxfee across the Bitcoin network (T)

BIPs, BOLTs and Proposals

• Bitcoin Encrypted Backup (E)

Lightning and L2

• A proposal for non-custodial ecash (J)
• Alpen’s Public Testnet is now live (J)
• ARK Labs documentation (J)
• Lightning swaps / ArkLabs HQ post (J)
• Lightning Swaps are the connective (J)
• Arkade OS documentation (J)
• Simplicity Launches on Liquid Mainnet (J)

Bitcoin Core

• index: Fix coinstats overflow #30469 (F)
• Add bitcoin-{node,gui} to release binaries for IPC #31802 (E)
• net, validation: don’t punish peers for consensus-invalid txs #33050 (E)
• policy: lower the default blockmintxfee, incrementalrelayfee, minrelaytxfee #33106 (E)
• kernel: create monolithic kernel static library #33077 (E)
• Introduce per-txin sighash midstate cache for legacy/p2sh/segwitv0 scripts #32473 (E)
• wallet, rpc: add v3 transaction creation and wallet support #32896 (E)
• signet: disk-space-DoS due to low mining difficulty #33266 (E)

We’ll meet at Massif Central Cafe.

• Open Street Map
• Google Maps
• Coordinates: 50.110097 8.679097

We’ll meet at Massif Central Cafe.

• Open Street Map
• Google Maps
• Coordinates: 50.110097 8.679097

We’ll meet at Massif Central Cafe.

• Open Street Map
• Google Maps
• Coordinates: 50.110097 8.679097

To start of the summer and outdoor season, we’ll meet at the Massif Central Cafe for the first time.

• Open Street Map
• Google Maps
• Coordinates: 50.110097 8.679097

We’ll host the third FFM Socratic Seminar.

These rules exist so that BitDevs participants can speak freely within the event:

• No photos, videos, or recordings.
• Chatham House Rule: you may reiterate the contents of the meeting without attribution.

Topics:

• Address Poisoning:
  • Bitcoin Address Poisoning Attacks
  • address poisoning transaction
• IBD Booster / SwiftSync PoC
• Mining Centralization
  • Invalid mining jobs by AntPool & friends during forks
  • Bitcoin Mining Centralization in 2025
• Bitcoin Core v29.0
  • versions 26.x and older are at “Maintenance End”
  • release notes
• HRF CISA Industry Report
• The Evolution of Payjoin
• Taproot DoS Vuln
• MEVpool
• GCC BIP
• Quantum Resistance Conversations
  • P2QRH / BIP-360 Update
  • Hashed Keys are Quantum Secure
  • Against Allowing Quantum Recovery of Bitcoin
• OP_CTV now or never?
  • Jonas Nick Technical Evaluation
  • CTV+CSFS Can we reach consensus?
  • The Ark case for CTV
  • Robin Linus comes around
  • Even Jeremy Rubin endorses CTV ;)
  • BIP-119 (OP_CHECKTEMPLATEVERIFY) (regtest only) #31989
  • BIP-348 (OP_CHECKSIGFROMSTACK) (regtest only) #32247

We’ll have two pleb talks along with our usual meetup.

Simon Satoshi will talk about “EuropeanBitcoiners - ein P2P Bildungsnetzwerk” (in German).

Dr. Matthias Linkerhand will present about Bitcoin in German politics and the initative “Bitcoin Bundesverband”.

There will be Glühwein (mulled wine), secret santa Bitcoin edition, and a trivia card game.

Veronika presents about Ark.

Slides (Google Drive)

João Thallis from BitDevs Porto Alegre is hosting a BitDevs in Frankfurt.

Topics:

• Bisq adds Lightning support: Bisq v2.1.0 adds the ability for users to settle trades using the Lightning Network.
  • https://github.com/bisq-network/bisq2/releases/tag/v2.1.0
• Samourai wallet fork
  • https://www.nobsbitcoin.com/ashigaru-v1-0-0/
• Soft-Fork/Covenant Dependent Layer 2 Review from Peter Todd
  • https://petertodd.org/2024/covenant-dependent-layer-2-review
• Bitcoin Core project disclosed three vulnerabilities fixed in v25.0
  • Public disclosure of three vulnerabilities affecting Bitcoin Core <v25.0
  • https://x.com/0xB10C/status/1844705899455062220
• Mining: Recent problems with testnet4
  • https://x.com/0xB10C/status/1849133671980339313
  • miner: Reorg Testnet4 minimum difficulty blocks
• Mutation-core: A mutation testing tool for Bitcoin Core
  • https://delvingbitcoin.org/t/mutation-core-a-mutation-testing-tool-for-bitcoin-core/1119
• Lightspark unveiled new L2, called Spark
  • https://x.com/kphur/status/1850001832787210365

We don’t have an talks planned for this meetup.

Bitcoin, ein Zahlungssystem: Wie man mit Bitcoin bezahlt und Zahlungen akzeptiert

In this presentation, Jens Leinert will talk about the various options for using Bitcoin for payments in bricks-and-mortar retail and online. He shows how Bitcoin can develop into a means of payment and presents various ways in which Bitcoin payments can already be accepted today.

About Jens Leinert Jens Leinert has spent his career in internet e-commerce and as a senior executive at payment providers. He has been passionate about Bitcoin since 2014 and runs an eCommerce agency specializing in Bitcoin projects. He founded Coinpages and Coincharge and is currently responsible for business development at Coinsnap. His goal is to promote the acceptance of Bitcoin payments and to support companies.

The presentation will be in German.

• Web: onleines.com
• Linkedin: https://linkedin.com/in/leinert
• Twitter: @leinert
• Nostr: npub1fdwm5pk3g9kxvfyqdxfma9qd6lydtdsjp0ggnk585ahzg0c7zspqqt78nl

We hope for good weather and will meet at the “Grünen Wiese am Mainufer gegenüber EZB” (50.1075616, 8.7036073, Open Street Maps, Google Maps) next to the European Central Bank. Bring blankets or other seating as there are not many benches. The sponsor for the beer is already found and fixed, so please bring some thirst as well as other food and drinks if needed!

In case of bad weather we still have the nearby indoor place as a backup.

We hope for good weather this time and will meet at the “Liegewiese an der Weseler Werft” (50.10775, 8.70107, Open Street Maps, Google Maps) next to the European Central Bank. Bring blankets or other seating as there are not many benches. The sponsor for the beer is already found and fixed, so please bring some thirst as well as other food and drinks if needed!

In case of bad weather we still have the nearby indoor place as a backup.

We hope for good weather this time and will meet at the “Liegewiese an der Weseler Werft” (50.10775, 8.70107, Open Street Maps, Google Maps) next to the European Central Bank. Bring blankets or other seating as there are not many benches. The sponsor for the beer is already found and fixed, so please bring some thirst as well as other food and drinks if needed!

In case of bad weather we still have the nearby indoor place as a backup.

Update: Due to the bad weather forcast we’ll meet at “RimeD Pizza und Kiosk” and walk to the original location if the weather turns out to be good.

We will meet at “Liegewiese an der Weseler Werft” (50.10775, 8.70107, Open Street Maps, Google Maps) next to the European Central Bank. Make sure to bring blankets to sit on as benches are limited. If you want, also bring a frisbee or similar outdoor games. There will be some beers, but probably not enough for the whole evening. Bring your own food and drinks!

In case of bad weather, we’ll go to a to-be-determined nearby indoor place.

Pre-halving party - the last meetup with 6.25 BTC block subsidy! Aaron van Wirdum will join us to showcase his new book “The Genesis Book”.

Starting at 19:15, Jochen will present on “DAOs im Bitcoin-Kontext - be your own exchange, fund, and everything”.

Starting at 19:15, genexyz_org will present on “Generational wealth - Nachlassplanung und Verwahrung”.

Starting at 19:15, Lightrider and Freerk from Ordimint will present on the topic “Ordinals and Inscriptions”.

Emzy, Timo, and Fabian are holding a Socratic Seminar.

Janik is presenting on “On-chain Analysis & Privacy”.

Mathias is giving a talk about “Self-Custody”, and Timo will explain new featues like P2P traffic encryption (BIP324) and assumeUTXO of Bitcoin Core v26.0.

We celebrate 10 years Bitcoin FFM. The meetup funders will join us for a Founders Panel.