diff --git a/lib/nntp/tiny/client.py b/lib/nntp/tiny/client.py
index 6ab015b..21814bf 100644
--- a/lib/nntp/tiny/client.py
+++ b/lib/nntp/tiny/client.py
@@ -3,10 +3,13 @@ import socket
 import ssl
 import datetime
 
+from typing import Optional
+
 from nntp.tiny.socket   import Connection
 from nntp.tiny.host     import Host
 from nntp.tiny.response import Response, ResponseCode
 from nntp.tiny.remote   import RemoteNewsgroup
+from nntp.tiny.message  import MessageRange
 
 class ClientException(Exception):
     pass
diff --git a/lib/nntp/tiny/session.py b/lib/nntp/tiny/session.py
index e59d0cb..d6a304e 100644
--- a/lib/nntp/tiny/session.py
+++ b/lib/nntp/tiny/session.py
@@ -199,19 +199,27 @@ class Session(Connection):
 
         return self.respond(ResponseCode.NNTP_ARTICLE_STAT_RESPONSE)
 
-    def _newsgroup_summary(self, newsgroup: Newsgroup) -> str:
+    def _newsgroup_summary(self, newsgroup: Newsgroup, since: Optional[datetime.datetime]=None) -> str:
         sql = """
             select
-                count(message_id),
-                min(message_id),
-                max(message_id)
+                count(newsgroup_message.message_id),
+                min(newsgroup_message.message_id),
+                max(newsgroup_message.message_id)
             from
-                newsgroup_message
+                newsgroup_message,
+                message
             where
-                newsgroup_id = ?
+                message.id = newsgroup_message.message_id
+                and newsgroup_message.newsgroup_id = ?
         """
 
-        cr  = self.db.execute(sql, (newsgroup.id,))
+        values = [newsgroup.id]
+
+        if since is not None:
+            sql += " and message.created_on >= ?"
+            values.append(since.isoformat())
+
+        cr  = self.db.execute(sql, values)
         row = cr.fetchone()
 
         return {
@@ -269,8 +277,8 @@ class Session(Connection):
 
         return self.end()
 
-    def print_newsgroup(self, newsgroup: Newsgroup):
-        summary = self._newsgroup_summary(newsgroup)
+    def print_newsgroup(self, newsgroup: Newsgroup, since: Optional[datetime.datetime]=None):
+        summary = self._newsgroup_summary(newsgroup, since)
 
         return self.print("%s %d %d %s" % (
             summary['name'],
@@ -485,13 +493,15 @@ class Session(Connection):
         elif len(args) > 1:
             return self.respond(ResponseCode.NNTP_SYNTAX_ERROR, "Too many arguments")
 
+        timestamp = self._parse_date_time(datestr, timestr)
+
         self.respond(ResponseCode.NNTP_GROUPS_NEW_FOLLOW)
 
         for name in self.server.newsgroups:
             if fnmatch.fnmatch(name, wildmat):
                 newsgroup = self.server.newsgroups[name]
 
-                self.print_newsgroup(newsgroup)
+                self.print_newsgroup(newsgroup, timestamp)
 
         return self.end()