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Although, speaking of Let's Encrypt, there will be a series of disruptive events over the next 18 months or so. * Soon (although when exactly I'm not sure because it has been delayed at least once) the Let's Encrypt systems will tell compliant ACME clients that the "correct" intermediate is Let's Encrypt's ISRG-signed X3 intermediate. This is a different certificate for the same X3 private key you're used to but not signed by the same trust root. If you use a correct client and have done things properly, this may cut off TLS clients for your systems that don't trust ISRG (the charity which runs Let's Encrypt). Six year old Android phones, the Windows XP system you know should have been retired, a VoIP desk phone running out-of-date firmware, stuff like that. * In March 2021 the X3 Intermediate expires. If your certificate software was not compliant with ACME, or you manually overrode it to use the old certificates to avoid the problem in the previous item, things break now. More things, and worse. Although... * Maybe before March 2021 the Let's Encrypt systems stop issuing from those soon-to-be-obsolete Intermediates and use newer ones instead perhaps named Y3 and Y4. In this case if you've jury rigged things (in an ACME non-compliant way) to keep using the old X3 intermediate that'll break suddenly after your renewal. Common web browsers may not trust the nonsense you're emitting, exactly which browsers break may vary depending on exactly what stupid things you did, but chances are you haven't tested and don't know. If you are using a compliant client then modern browsers are all fine, but archaic stuff breaks suddenly. * In September 2021 the DST Root X3 root expires. If you have somehow clung on to trust via this root, whether through your own effort or via trust path discovery code inside client systems, that goes away instantly. Any systems that don't trust ISRG will refuse to trust your certificates, no matter how often you re-issue them and reconfigure things, those clients themselves need updating urgently and you probably have no way to do that. Oops. |