diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index caf7da0..f101575 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -20,6 +20,7 @@ jobs:
             3.2,
             3.3,
             3.4,
+            '4.0',
             jruby,
           ]
         exclude:
diff --git a/Gemfile.lock b/Gemfile.lock
index a77b658..77b6be0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -14,10 +14,10 @@ GEM
     minitest (6.0.1)
       prism (~> 1.5)
     parallel (1.27.0)
-    parser (3.3.10.0)
+    parser (3.3.10.1)
       ast (~> 2.4.1)
       racc
-    prism (1.7.0)
+    prism (1.9.0)
     racc (1.8.1)
     racc (1.8.1-java)
     rainbow (3.1.1)