diff --git a/src/Composer/Util/Hg.php b/src/Composer/Util/Hg.php
index 8c2412239..76d063dbe 100644
--- a/src/Composer/Util/Hg.php
+++ b/src/Composer/Util/Hg.php
@@ -107,7 +107,7 @@ class Hg
     {
         if (false === self::$version) {
             self::$version = null;
-            if (0 === $process->execute('hg --version', $output) && Preg::isMatch('/^.+? (\d+(?:\.\d+)+)\)?\r?\n/', $output, $matches)) {
+            if (0 === $process->execute('hg --version', $output) && Preg::isMatch('/^.+? (\d+(?:\.\d+)+)(?:\+.*?)?\)?\r?\n/', $output, $matches)) {
                 self::$version = $matches[1];
             }
         }