Does anyone still need testnet3?

The discussion revolves around the challenges the lightning network faces, particularly with the issue of migrating to newer test networks, such as testnet4. This migration issue is notably problematic due to the necessity for coordinated action among various parties involved in the lightning network, each with their own set of priorities. The reliance on interoperability makes this coordination crucial for any significant moves or updates. Furthermore, the need for the latest Bitcoin Core versions to leverage new policy features emphasizes the inadequacy of relying on older versions like v29 through back-ports as a sustainable strategy.

The suggestion put forward involves the lightning industry considering the organization of a custom signet to alleviate these migration challenges. Two potential structures for this custom signet are proposed: one based on a 1-of-N configuration with keys distributed among current players, and the other being an unsigned proof-of-work system. The latter might present more initial setup difficulties but offers an inviting entry point for future participants. The benefits of establishing such a network include indefinite operation and easier coordination for its eventual replacement. Additionally, it would provide a platform for testing soft fork proposals at a pace aligned with the Bolt specification work, similar to how tests are conducted on the default signet but tailored to the specific needs of the lightning network.