NEWS: news for Xapian 1.4 enabled features

In fact some of these features are available in Xapian 1.3.x development
releases, but these are not really widely packaged. In any case, the
experts who are using development releases of Xapian can figure that
out.

NEWS

@@ -1,6 +1,42 @@
 Notmuch 0.23 (UNRELEASED)
 =========================
 
+General (Xapian 1.4+)
+---------------------
+
+Compiling against Xapian 1.4 enables several new features.
+
+Support for single argument date: queries
+
+  `date:<expr>` is equivalent to  `date:<expr>..<expr>`.
+
+Support for blocking opens
+
+  When opening a database notmuch by default will wait for another
+  process to release a write lock, rather than returning an error.
+
+Support for named queries
+
+  Named queries (also known as 'saved searches') can be defined with a
+  `query:name` format. The expansion of these queries is stored in the
+  database and they can be used from any notmuch client.
+
+CLI
+---
+
+Support for compile time options
+
+  A group of `built_with` keys is now supported for notmuch
+  config. Initial keys in this group are `compact`, `field_processor`,
+  and `retry_lock`.
+
+Dump/Restore support for configuration information
+
+  Any configuration information stored in the database (initially just
+  named queries) is dumped and restored. Any new information in the
+  dump format is prefixed by '#' to allow existing scripts to ignore
+  it.
+
 Emacs
 -----