diff --git a/doc/api/dgram.markdown b/doc/api/dgram.markdown
index bcc3dcae5b..707f348865 100644
--- a/doc/api/dgram.markdown
+++ b/doc/api/dgram.markdown
@@ -6,6 +6,21 @@
 
 Datagram sockets are available through `require('dgram')`.
 
+Important note: the behavior of `dgram.Socket#bind()` has changed in v0.10
+and is always asynchronous now.  If you have code that looks like this:
+
+    var s = dgram.createSocket('udp4');
+    s.bind(1234);
+    s.addMembership('224.0.0.114');
+
+You have to change it to this:
+
+    var s = dgram.createSocket('udp4');
+    s.bind(1234, function() {
+      s.addMembership('224.0.0.114');
+    });
+
+
 ## dgram.createSocket(type, [callback])
 
 * `type` String. Either 'udp4' or 'udp6'