diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index 115301f..d79de23 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -4,7 +4,7 @@ on:
   pull_request:
   push:
     branches:
-      - "master"
+    - "master"
 
 jobs:
   phpunit:
@@ -22,6 +22,9 @@ jobs:
           - "7.3"
           - "7.4"
           - "8.0"
+          - "8.1"
+          - "8.2"
+          - "8.3"
         operating-system:
           - "ubuntu-latest"
 
diff --git a/composer.json b/composer.json
index 793c66e..be27a33 100644
--- a/composer.json
+++ b/composer.json
@@ -47,14 +47,15 @@
         "php-http/message": "^1.5",
         "php-http/message-factory": "^1.1",
         "php-http/discovery": "^1.14",
-        "symfony/http-foundation": "^2.1|^3|^4|^5|^6",
+        "symfony/http-foundation": "^2.1|^3|^4|^5|^6|^7",
         "moneyphp/money": "^3.1|^4.0.3"
     },
     "require-dev": {
         "omnipay/tests": "^4.1",
-        "php-http/mock-client": "^1",
+        "php-http/mock-client": "^1.6",
         "php-http/guzzle7-adapter": "^1",
-        "squizlabs/php_codesniffer": "^3.5"
+        "squizlabs/php_codesniffer": "^3.8.1",
+        "http-interop/http-factory-guzzle": "^1.1"
     },
     "extra": {
         "branch-alias": {
@@ -70,5 +71,10 @@
         "fix-style": "phpcbf -p --standard=PSR2 src/"
     },
     "minimum-stability": "dev",
-    "prefer-stable": true
+    "prefer-stable": true,
+    "config": {
+        "allow-plugins": {
+            "php-http/discovery": true
+        }
+    }
 }