@glasser @Majkl I’m sorry to hear that this caused you problems. The ACME protocol (as discussed in the thread @schoen linked to) provides enough information during the registration flow that you do not need to hardcode the ToS string. Compliant clients will not encounter outages from a ToS change if they use this method instead of hardcoding the URL.
I definitely recommend that approach moving forward! Again, apologies for the trouble. We will likely change the way we roll out a ToS update in the future to account for some of the buggy client implementations.