TTL limit actually isn't sent.

src/App/DNSZone.purs

@@ -15,9 +15,6 @@ type DNSZone
 
     -- Each resource record has a number, this is the ID to give to a new RR.
     , current_rrid  :: Int
-
-    -- Minimum TTL accepted for a resource record.
-    , ttl_limit_min :: Int
     }
 
 codec :: JsonCodec DNSZone
@@ -26,5 +23,4 @@ codec = CA.object "DNSZone"
     { domain:        CA.string
     , resources:     CA.array RR.codec
     , current_rrid:  CA.int
-    , ttl_limit_min: CA.int
     })