They mention that they have written a test to verify the behavior on the core mempool and it has worked as expected. They provide a link to the commit on GitHub for reference.

The sender also mentions the responsible disclosure process that they have followed, which is similar to the process documented for the Linux kernel. They provide a link to the documentation on embargoed hardware issues for further information.

Furthermore, they inform that they are halting their involvement with the development of the lightning network and its implementations, including coordinating the handling of security issues at the protocol level. They have closed an old issue related to this purpose on the bolt repository and provide a link to it.

The sender expresses concern about a new class of replacement cycling attacks that puts lightning in a perilous position. They believe that a sustainable fix can only happen at the base-layer, such as adding a memory-intensive history of all-seen transactions or a consensus upgrade. They acknowledge that deployed mitigations are effective against simple attacks but may not be sufficient against advanced attackers, as mentioned in a previous full disclosure mail.

They emphasize that changes of this nature require transparency and buy-in from the community as a whole, as they impact the processing requirements of full-nodes and the security architecture of the decentralized bitcoin ecosystem. However, explaining why these changes are necessary for the lightning network and designing them well would require disclosing practical and critical attacks on a large public BTC ecosystem, which presents a hard dilemma.

The sender states their intention to remain silent on these issues on public mailing lists until the week of October 30th, as enough material has already been published and other experts are available. Afterward, they plan to shift their focus back to Bitcoin Core development.

Overall, the email highlights the sender's test verification, responsible disclosure process, decision to step away from lightning network development, concerns about replacement cycling attacks, the need for community involvement in making changes, and their future plans.