Subject: [Acme] "mailto" mandatory to implement

From: Daniel McCarney <[email-masked]>
Date: Tue, 4 Apr 2017 15:33:25 -0400

Following up on the draft minutes[0] item for server contact support from
the meeting at IETF98:

"""
- **Advertise server contact support** (slide 19)
  - Discussion: Ted highlights the risk of failure in negotiation (empty
intersection) a single MTI scheme is necessary and sufficient for interop
  - **Decision** is to REQUIRE `mailto` as URL scheme so that it's always
possible to fall back to it
"""

I submitted https://github.com/ietf-wg-acme/acme/pull/291 to cover this &
add an unsupported contact protocol error type.

[0] - https://mailarchive.ietf.org/arch/msg/acme/wO4AAJxnGEDT4LZQbIAbm4xXods

- daniel