Report on the event dedicated to Bitcoin protocol’s main layer 2, organized by Fulgur Ventures.
The Tuscany Lightning Summit 2025, held on May 7-8 in Viareggio and organized by Fulgur Ventures, brought together developers and experts in Bitcoin and Lightning Network.
The opening speech by Giacomo Zucco, director of Plan B Network, explored the role of LN as the “global common language of the Bitcoin economy.” Zucco presented an analysis of on-chain and off-chain approaches, highlighting the limitations of the original LN design proposed by Poon and Dryja.
“The initial structure of LN had limitations,” Zucco explained. “It was limited to transactions between two parties, with locked liquidity and the need for channel rebalancing.” According to Zucco, the Lightning Network has evolved into a “network of global exchange” that connects different security models.
Zucco illustrated new development directions, particularly the shift to Taproot channels to improve transaction privacy. “If asset exchange on LN catches on, Taproot channels will also be adopted,” he stated.
He presented several models of security, custody, and Bitcoin usage:
- Swaps and submarine swaps;
- Cashu (custodial model based on Chaumian Mint);
- Fedimint (federated model);
- Liquid (non-fractional reserve federation);
- Statechain (used in Mercury Wallet);
- Ark (defined as “trustless in a relevant time window”).
According to Zucco, the trend is toward developing wallets that manage payments autonomously, citing Blitz Wallet as an example of an interface that handles transactions from Cashu, Liquid, LN, and on-chain. “The security model should adapt to the amount of funds: less security for small amounts, greater security for higher amounts.”
He discussed the privacy issues of HTLCs (Hashed Timelock Contracts) and the need to move to PTLCs (Point Timelock Contracts). “Taproot channels represent a local upgrade, while PTLCs are a structural change to LN,” he specified.
Zucco concluded by mentioning the progress of BOLT 12, particularly for asynchronous payments on offline mobile devices. He cited Phoenix as an example of a wallet implementing the BOLT 12 contacts functionality and emphasized the usefulness of BIP 21 as a universal QR code.
The second day of the summit began with a conversation between Stephan Livera and Adam Back, focusing on LN and the recent debate on the OP_RETURN controversy.
Regarding the removal of the limit on the OP_RETURN field, Back addressed the issue of communication between developers and the community: “The communication was handled badly. The debate should have started a year ago. Some developers believe that community consensus is not necessary to implement standardness changes, but bitcoiners don’t like changes.”
The Blockstream CEO compared the situation to email spam:
“We all hate spam in emails, but we can’t completely stop it. That doesn’t mean we have to give up. We have filters, we have heuristics, we block banners, so we try, right? We can’t win absolutely, but we can reduce it by trying.”
In the second part of the conversation, Back discussed the interoperability between various layer 2 solutions in the Bitcoin ecosystem. The creator of HashCash described LN as connection infrastructure between different layer 2 solutions, explaining how it allows funds to move instantly between protocols like Cashu, Liquid, Ark, and Fedimint.
A trend highlighted by Back concerns wallets like Aqua that have adopted the “nodeless” model, continuously performing swaps between Liquid, on-chain, and LN. “With this type of wallet, it’s no longer necessary to manage a node and Lightning channels. This represents an improvement in user experience,” he explained.
The two days concluded with an open session that allowed interactions between participants and speakers, with various panels dedicated particularly to the development of the RGB protocol.
