diff --git a/lib/rss/rexmlparser.rb b/lib/rss/rexmlparser.rb
index 5a8cc2ac5a..13ab0e277b 100644
--- a/lib/rss/rexmlparser.rb
+++ b/lib/rss/rexmlparser.rb
@@ -1,7 +1,7 @@
 require "rexml/document"
 require "rexml/streamlistener"
 
-/\A(\d+)\.(\d+)(?:.\d+)+\z/ =~ REXML::Version
+/\A(\d+)\.(\d+)(?:\.\d+)+\z/ =~ REXML::Version
 if ([$1.to_i, $2.to_i] <=> [2, 5]) < 0
 	raise LoadError, "needs REXML 2.5 or later (#{REXML::Version})"
 end