diff --git a/README.md b/README.md
index 588f887..917d5c2 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,7 @@ The Google Client uses a few methods to determine how it should authenticate wit
 ### Public URLs
 
 The adapter implements a `getUrl($path)` method which returns a public url to a file.
+>**Note:** Method available for Laravel 5.2 and higher. If used on 5.1, it will throw an exception.
 
 ```php
 $disk = Storage::disk('gcs');
@@ -105,5 +106,5 @@ $disk->move('old/file1.jpg', 'new/file1.jpg');
 // get url to file
 $url = $disk->url('folder/my_file.txt');
 
-// see https://laravel.com/docs/5.3/filesystem for full list of available functionality
+// See https://laravel.com/docs/5.3/filesystem for full list of available functionality
 ```
diff --git a/composer.json b/composer.json
index 4dd3ce2..cd26b83 100644
--- a/composer.json
+++ b/composer.json
@@ -10,9 +10,9 @@
   ],
   "require": {
     "php": ">=5.5.9",
-    "illuminate/support": "^5.2|^5.3",
+    "illuminate/support": "^5.1|^5.2|^5.3",
     "superbalist/flysystem-google-storage": "^3.0|^4.0",
-    "illuminate/filesystem": "^5.2|^5.3"
+    "illuminate/filesystem": "^5.1|^5.2|^5.3"
   },
   "autoload": {
     "psr-4": {