+XAPIAN FIELD PROCESSORS
+=======================
+
+Certain optional features of the notmuch query processor rely on the
+presence of the Xapian field processor API. You can determine if your
+notmuch was built against a sufficiently recent version of Xapian by running
+
+::
+
+ % notmuch config get built_with.field_processor
+
+Currently the following features require field processor support:
+
+- non-range date queries, e.g. "date:today"
+- named queries e.g. "query:my_special_query"
+