diff --git a/composer.json b/composer.json
index c1686d0..896f112 100644
--- a/composer.json
+++ b/composer.json
@@ -13,6 +13,9 @@
             "RomansTest\\": "test"
         }
     },
+    "require": {
+        "php": "^7.0"
+    },
     "require-dev": {
         "phpunit/phpunit": "6.1.*"
     },
diff --git a/composer.lock b/composer.lock
index 0682aaa..cd3016e 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "content-hash": "1a4029661fca7bc197d0fe99bd0b0c1e",
+    "content-hash": "31d5762f5c4b3b5f1221a42bcdbc29a5",
     "packages": [],
     "packages-dev": [
         {
@@ -1421,6 +1421,8 @@
     "stability-flags": [],
     "prefer-stable": false,
     "prefer-lowest": false,
-    "platform": [],
+    "platform": {
+        "php": "^7.0"
+    },
     "platform-dev": []
 }