diff --git a/Dockerfile b/Dockerfile
index bb651d0fe..0f141dbcd 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,7 +7,7 @@ RUN set -xe \
     && composer require guzzlehttp/guzzle
 
 
-FROM php:7.3
+FROM php:7.4
 
 WORKDIR /guzzle
 
diff --git a/docs/overview.rst b/docs/overview.rst
index 64d364dc1..cf24b5b6c 100644
--- a/docs/overview.rst
+++ b/docs/overview.rst
@@ -39,7 +39,7 @@ You can add Guzzle as a dependency using Composer:
 
 .. code-block:: bash
 
-    composer require guzzlehttp/guzzle:^7.0
+    composer require guzzlehttp/guzzle:^8.0
 
 Alternatively, you can specify Guzzle as a dependency in your project's
 existing composer.json file:
@@ -48,7 +48,7 @@ existing composer.json file:
 
     {
       "require": {
-         "guzzlehttp/guzzle": "^7.0"
+         "guzzlehttp/guzzle": "^8.0"
       }
    }
 
@@ -66,13 +66,13 @@ Bleeding edge
 -------------
 
 During your development, you can keep up with the latest changes on the master
-branch by setting the version requirement for Guzzle to ``^7.0@dev``.
+branch by setting the version requirement for Guzzle to ``^8.0@dev``.
 
 .. code-block:: js
 
    {
       "require": {
-         "guzzlehttp/guzzle": "^7.0@dev"
+         "guzzlehttp/guzzle": "^8.0@dev"
       }
    }
 
diff --git a/src/ClientInterface.php b/src/ClientInterface.php
index 7f0a3fbd4..547c5a0b0 100644
--- a/src/ClientInterface.php
+++ b/src/ClientInterface.php
@@ -16,7 +16,7 @@ interface ClientInterface
     /**
      * The Guzzle major version.
      */
-    public const MAJOR_VERSION = 7;
+    public const MAJOR_VERSION = 8;
 
     /**
      * Send an HTTP request.