diff --git a/composer.json b/composer.json
index 8a33b16..3d1a644 100644
--- a/composer.json
+++ b/composer.json
@@ -28,10 +28,10 @@
   "require": {
     "php": ">=5.3.0",
     "slim/slim": "~2.0",
-    "voku/portable-utf8": "~3.0"
+    "voku/portable-utf8": "~3.1"
   },
   "require-dev": {
-    "phpunit/phpunit": "~4.0"
+    "phpunit/phpunit": "~4.0|~5.0"
   },
   "autoload": {
     "psr-4": {