Please take care when deploying Let's Encrypt certificates...

[Viktor Dukhovni]

If you've published DANE TLSA records for your current certificate
chain, and are considering switch to Let's Encrypt issued certificates,
please do not forget:

    https://dane.sys4.de/common_mistakes#3

    https://tools.ietf.org/html/rfc7671#section-8.1

I've seen more than one of the early adopters of LE certificates
neglect to update their TLSA records (a few TTLs) *before* deploying
the new LE certificate chain.

-- 
	Viktor.