diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1797f466..d59d02a9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -91,6 +91,7 @@ jobs:
                 php-version:
                     - '7.3'
                     - '7.4'
+                    - '8.0'
 
         steps:
             -
diff --git a/composer.json b/composer.json
index 9fb89caf..1a45f93e 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     "require": {
         "php": "^7.3 || ^8.0",
         "phpactor/class-to-file": "~0.4.0",
-        "phpactor/container": "^1.0",
+        "phpactor/container": "~1.3.4",
         "phpactor/reference-finder": "^0.1.5",
         "phpactor/source-code-filesystem": "~0.1.6",
         "phpactor/text-document": "~1.2.3",