diff --git a/composer.json b/composer.json
index 5345f64..2b89deb 100644
--- a/composer.json
+++ b/composer.json
@@ -26,7 +26,7 @@
 	"sabberworm/php-css-parser": "*",
 	"phpmailer/phpmailer": "*",
 	"almasaeed2010/adminlte": "*",
-	"twbs/bootstrap": ">=4.0.0",
+	"twbs/bootstrap": "4.0.0-alpha.6",
 	"components/jquery": ">=2.1.0",
 	"components/jqueryui": ">=1.11.1",
 	"components/font-awesome": ">=4.0.0",