diff --git a/composer.json b/composer.json
index 7aaeb41135..962ed78ef6 100644
--- a/composer.json
+++ b/composer.json
@@ -21,15 +21,19 @@
     ],
     "require": {
         "php": ">=5.3.0",
-        "ext-xml": "*"
+        "ext-xml": "*",
+        "ext-zip": "*"
     },
     "require-dev": {
         "phpunit/phpunit": "3.7.*"
     },
     "recommend": {
-        "ext-zip": "*",
         "ext-gd2": "*"
     },
+    "suggest": {
+        "ext-xmlwriter": "*",
+        "ext-xsl": "*"
+    },
     "autoload": {
         "psr-0": {
             "PHPWord": "Classes/"