diff --git a/composer.json b/composer.json
index 8b6d5da..e11f64d 100644
--- a/composer.json
+++ b/composer.json
@@ -13,9 +13,8 @@
   ],
   "require": {
     "behat/mink": "~1.5",
-    "behat/behat": "~3.4.0",
-    "behat/mink-extension": "~2.0",
-    "symfony/dependency-injection": "~3.2"
+    "behat/behat": "^3.4.0",
+    "behat/mink-extension": "~2.0"
   },
   "require-dev": {
     "phpspec/phpspec": "~2.0"
diff --git a/src/Behat/DomainExtension/config/services.yml b/src/Behat/DomainExtension/config/services.yml
index 191dfc0..1de1248 100644
--- a/src/Behat/DomainExtension/config/services.yml
+++ b/src/Behat/DomainExtension/config/services.yml
@@ -7,8 +7,8 @@ parameters:
 
 services:
   domain.context.initializer:
-    class: %domain.context.initializer.class%
+    class: '%domain.context.initializer.class%'
     arguments:
-      - %domain.domain_map%
+      - '%domain.domain_map%'
     tags:
       - { name: context.initializer }