diff --git a/.circleci/config.yml b/.circleci/config.yml
index 795d505..f6dc6f6 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -6,7 +6,7 @@ jobs:
   build:
     working_directory: ~/drupal-skeleton
     docker:
-      - image: cimg/php:7.4-browsers
+      - image: cimg/php:8.1-browsers
       - image: cimg/mysql:5.7
         command: --max_allowed_packet=16M
         environment:
diff --git a/.ddev/config.yaml b/.ddev/config.yaml
index 0f0fc88..e97ac82 100644
--- a/.ddev/config.yaml
+++ b/.ddev/config.yaml
@@ -17,7 +17,7 @@ webserver_type: apache-fpm
 #mariadb_version: "10.3"
 
 # TODO: Make sure this PHP version matches the project's hosting environment.
-php_version: "7.4"
+php_version: "8.1"
 
 # Add any multisite subdomains to this array. Adding "example" will make this environment
 # available at "example.ddev.site".
diff --git a/README.md b/README.md
index 8291019..28ffa47 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ You should have the development dependencies installed on your Mac before you be
 
 The development dependencies are:
 
-* PHP 7.4+
+* PHP 8.1+
   * Check your PHP version from the command line using `php --version`
 * [XCode](https://itunes.apple.com/us/app/xcode/id497799835?mt=12)
 * [Composer](https://getcomposer.org/download/)
diff --git a/composer.json b/composer.json
index 5373fca..e2e7a1a 100644
--- a/composer.json
+++ b/composer.json
@@ -47,10 +47,11 @@
             "composer/installers": true,
             "drupal/core-composer-scaffold": true,
             "cweagans/composer-patches": true,
-            "dealerdirect/phpcodesniffer-composer-installer": true
+            "dealerdirect/phpcodesniffer-composer-installer": true,
+            "phpstan/extension-installer": true
         },
         "platform": {
-            "php": "7.4"
+            "php": "8.1"
         },
         "preferred-install": {
             "*": "dist"