[Update 2018-01-18: The most up-to-date summary is at IMPORTANT: What you need to know about TLS-SNI validation issues] Please see this post for background information. The last 48 hours have been a busy time for Let’s Encrypt staff. We’ve been working hard to come up with a plan for ACME TLS-SNI validation that sufficiently protects the integrity of Web PKI while minimizing problems for people an