diff --git a/.travis.yml b/.travis.yml
index e0f45b1e0df..4630e91bffd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,8 +11,6 @@ env:
     - TEST_COMMAND="vendor/bin/phpunit --verbose --coverage-text"
 
 php:
-  - 5.6
-  - 7.0
   - 7.1
   - 7.2
   - 7.3
diff --git a/README.md b/README.md
index f488dcc8ff6..47ff1282522 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Uses [GitHub API v3](http://developer.github.com/v3/) & supports [GitHub API v4]
 
 ## Requirements
 
-* PHP >= 5.6
+* PHP >= 7.1
 * A [HTTP client](https://packagist.org/providers/php-http/client-implementation)
 * A [PSR-7 implementation](https://packagist.org/providers/psr/http-message-implementation)
 * (optional) PHPUnit to run tests.
diff --git a/composer.json b/composer.json
index 1e701df8b7c..238b6aba771 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
         }
     ],
     "require": {
-        "php": "^5.6 || ^7.0",
+        "php": "^7.1",
         "psr/http-message": "^1.0",
         "psr/cache": "^1.0",
         "php-http/httplug": "^1.1",
@@ -27,7 +27,7 @@
         "php-http/cache-plugin": "^1.4"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.5 || ^6.0",
+        "phpunit/phpunit": "^6.0",
         "php-http/guzzle6-adapter": "^1.0",
         "php-http/mock-client": "^1.0",
         "guzzlehttp/psr7": "^1.2",