diff --git a/.travis.yml b/.travis.yml
index 4630e91bffd..84c5687f812 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,6 @@ sudo: false
 
 cache:
   directories:
-    - vendor
     - $HOME/.composer/cache
 
 env:
diff --git a/composer.json b/composer.json
index af0e7df5ad9..eeaa0d88d92 100644
--- a/composer.json
+++ b/composer.json
@@ -20,7 +20,7 @@
         "php": "^7.1",
         "psr/http-message": "^1.0",
         "psr/cache": "^1.0",
-        "php-http/httplug": "^1.1",
+        "php-http/httplug": "^1.1 || ^2.0",
         "php-http/discovery": "^1.0",
         "php-http/client-implementation": "^1.0",
         "php-http/client-common": "^1.6",