diff --git a/.travis.yml b/.travis.yml
index 59a815c..2799dfe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,12 @@
+dist: trusty
 language: php
 
 php:
-  - 5.3
   - 5.4
   - 5.5
   - 5.6
   - 7.0
+  - 7.1
   - hhvm
 
 before_script: composer install --dev
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a040f6d..8d0b89b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -10,7 +10,7 @@
     cd tests && php all_tests.php && cd ..
     ```
 
-    The [Travis CI build](https://travis-ci.org/campaignmonitor/createsend-php) runs on PHP `5.3` and `5.4`.
+    The [Travis CI build](https://travis-ci.org/campaignmonitor/createsend-php) runs on PHP `5.4`, `5.5`, `5.6`, `7.0`, `7.1` and `hhvm`.
 
 5. It should go without saying, but do not increment the version number in your commits.
 6. [Submit a pull request](https://help.github.com/articles/using-pull-requests).
diff --git a/composer.json b/composer.json
index 993dea5..530f3ac 100644
--- a/composer.json
+++ b/composer.json
@@ -13,10 +13,10 @@
         }
     ],
     "require": {
-        "php": ">=5.3.0"
+        "php": ">=5.4.0"
     },
     "require-dev": {
-        "simpletest/simpletest": "~1.1.3"
+        "simpletest/simpletest": "~1.1.7"
     },
     "autoload": {
         "classmap": [
diff --git a/composer.lock b/composer.lock
index 22193fd..0e96129 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1,57 +1,94 @@
 {
     "_readme": [
         "This file locks the dependencies of your project to a known state",
-        "Read more about it at http://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file"
-    ],
-    "hash": "eccad7521596b5fe0d81af51ab2f16a1",
-    "packages": [
-
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
+        "This file is @generated automatically"
     ],
+    "hash": "0a1730e0be589c55a51aa92f146da77b",
+    "content-hash": "26fecab2d6ff4273664cc3afab6660d9",
+    "packages": [],
     "packages-dev": [
         {
             "name": "simpletest/simpletest",
-            "version": "1.1.3",
+            "version": "v1.1.7",
             "source": {
                 "type": "git",
-                "url": "https://github.com/simpletest/simpletest",
-                "reference": "1.1.3"
+                "url": "https://github.com/simpletest/simpletest.git",
+                "reference": "2f8c466c114bdb9c11028a0c3e6d1380ae6a18dc"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://github.com/simpletest/simpletest/zipball/1.1.3",
-                "reference": "1.1.3",
+                "url": "https://api.github.com/repos/simpletest/simpletest/zipball/2f8c466c114bdb9c11028a0c3e6d1380ae6a18dc",
+                "reference": "2f8c466c114bdb9c11028a0c3e6d1380ae6a18dc",
                 "shasum": ""
             },
             "require": {
                 "php": ">=5.0.5"
             },
+            "replace": {
+                "lastcraft/simpletest": "self.version",
+                "vierbergenlars/simpletest": "self.version"
+            },
             "type": "library",
+            "autoload": {
+                "classmap": [
+                    "."
+                ]
+            },
             "notification-url": "https://packagist.org/downloads/",
             "license": [
                 "LGPL-2.0+"
             ],
             "authors": [
+                {
+                    "name": "Lars Vierbergen",
+                    "email": "vierbergenlars@gmail.com"
+                },
+                {
+                    "name": "Lachlan Donald",
+                    "email": "lachlan@ljd.cc"
+                },
                 {
                     "name": "Marcus Baker",
-                    "email": "marcus@lastcraft.com"
+                    "email": "marcus@lastcraft.com",
+                    "role": "Original project lead"
+                },
+                {
+                    "name": "Jason Sweat",
+                    "role": "Original developer"
+                },
+                {
+                    "name": "Travis Swicegood",
+                    "role": "Original developer"
+                },
+                {
+                    "name": "Perrick Penet",
+                    "role": "Original developer"
+                },
+                {
+                    "name": "Edward Z. Yang",
+                    "role": "Original developer"
                 }
             ],
             "description": "Unit testing, mock objects and web testing framework for PHP built around test cases.",
             "homepage": "http://simpletest.org/",
-            "time": "2012-06-11 22:22:54"
+            "keywords": [
+                "SimpleTest",
+                "code-coverage",
+                "selenium",
+                "testing",
+                "unit-test"
+            ],
+            "time": "2015-09-21 18:19:52"
         }
     ],
-    "aliases": [
-
-    ],
+    "aliases": [],
     "minimum-stability": "stable",
-    "stability-flags": [
-
-    ],
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
     "platform": {
-        "php": ">=5.3.0"
+        "php": ">=5.4.0"
     },
-    "platform-dev": [
-
-    ]
+    "platform-dev": []
 }
diff --git a/tests/all_tests.php b/tests/all_tests.php
index 4a7e1e9..b71c9d9 100644
--- a/tests/all_tests.php
+++ b/tests/all_tests.php
@@ -4,8 +4,8 @@
 require_once __DIR__.'/../vendor/simpletest/simpletest/mock_objects.php';
 
 class AllTests extends TestSuite {
-    function AllTests() {
-        $this->TestSuite('All Tests');
+    function __construct() {
+        parent::__construct('All Tests');
         $this->addFile('class_tests/transport_test.php');
         $this->addFile('class_tests/response_tests.php');
         $this->addFile('csrest_test.php');
diff --git a/tests/csrest_test.php b/tests/csrest_test.php
index b1c124f..78343b2 100644
--- a/tests/csrest_test.php
+++ b/tests/csrest_test.php
@@ -2,6 +2,7 @@
 
 require_once __DIR__.'/../vendor/autoload.php';
 require_once __DIR__.'/../vendor/simpletest/simpletest/autorun.php';
+require_once(__DIR__.'/../vendor/simpletest/simpletest/mock_objects.php');
 
 @Mock::generate('CS_REST_Log');
 @Mock::generate('CS_REST_NativeJsonSerialiser');