On Thu 2019-05-23 07:50:43 -0300, David Bremner wrote:
> Daniel Kahn Gillmor <dkg@fifthhorseman.net> writes:
>
>>      headers:        headers,
>> +    crypto?:        crypto,   # omitted if crypto disabled, or if no part was signed or encrypted.
>>      body?:          [part]    # omitted if --body=false
>>  }
>
> I'm wondering about the "upward compatible" aspect of this. If the
> crypto key is ommitted, a client doesn't know whether to interpret that
> as no part was signed or encrypted, or just an older version of notmuch.

I understand your concern here.  Would making
notmuch_built_with("message_crypto_summary") return true solve the
problem?

        --dkg