As @josh notes, we’ll be making a very minor update to our subscriber agreement on November 15, 2017. This should be transparent to almost all API users. You do not need to re-agree to the new subscriber agreement.
Last time we updated the subscriber agreement, there were a handful of clients that tried to explicitly re-agree once we updated the subscriber agreement URL, producing errors. The ACME spec has been clarified to indicate that’s not necessary, and I believe the affected clients have been fixed.
If you run into issues, please start a thread here on the forum. Thanks!