Mention immutable rdata.

diff --git a/differences.md b/differences.md
index 89e0e80c0545af07176817965cc2013dd2c2eaf8..18c02cde87c6d5376b31b6d11aaf323886c5c90a 100644 (file)
--- a/differences.md
+++ b/differences.md
@@ -8,3 +8,7 @@ in the python 2 style on both python 2 and 3.
 # Removed hash module
 
 dns.hash module was removed. Use Python built in hashlib instead.
+
+# dns.rdata.Rdata instances are now immutable
+
+The replace() method can be used to create copies with changes.