diff --git a/.travis.yml b/.travis.yml
index fb8310c..08adabb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,8 @@ php:
   - 5.6
   - 5.5
   - 5.4
+  - 7.0
+  - 7.1
   - hhvm
 
 install: composer require --no-update guzzlehttp/guzzle $GUZZLE_VERSION; composer update
@@ -14,3 +16,16 @@ env:
   - GUZZLE_VERSION: 4.2
   - GUZZLE_VERSION: 5.0
   - GUZZLE_VERSION: 5.2
+  - GUZZLE_VERSION: 5.3
+  - GUZZLE_VERSION: 5.3.1
+
+matrix:
+  exclude:
+    - php: 7.1
+      env: GUZZLE_VERSION=4.2
+    - php: 7.1
+      env: GUZZLE_VERSION=5.0
+    - php: 7.1
+      env: GUZZLE_VERSION=5.2
+    - php: 7.1
+      env: GUZZLE_VERSION=5.3
diff --git a/composer.json b/composer.json
index 42a3426..2920b43 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
     "require": {
         "php": ">=5.4.0",
         "99designs/http-signatures": ">=1.1.0 <3.0.0",
-        "guzzlehttp/guzzle": ">=4.2.0 <5.3.0"
+        "guzzlehttp/guzzle": ">=4.2.0 <=5.3.1"
     },
     "require-dev": {
         "phpunit/phpunit": "~4.1"