diff --git a/README.md b/README.md
index ff8dd7c..31951f5 100644
--- a/README.md
+++ b/README.md
@@ -42,14 +42,14 @@ jobs:
       - name: Set up Helm
         uses: azure/setup-helm@v1
         with:
-          version: v3.7.2
+          version: v3.8.1
 
       - uses: actions/setup-python@v2
         with:
           python-version: 3.7
 
       - name: Set up chart-testing
-        uses: helm/chart-testing-action@v2.2.0
+        uses: helm/chart-testing-action@v2.2.1
 
       - name: Run chart-testing (list-changed)
         id: list-changed
diff --git a/action.yml b/action.yml
index a1a9a8b..ca462de 100644
--- a/action.yml
+++ b/action.yml
@@ -6,8 +6,9 @@ branding:
   icon: anchor
 inputs:
   version:
-    description: "The chart-testing version to install (default: v3.5.0)"
-    default: v3.5.0
+    description: "The chart-testing version to install (default: v3.5.1)"
+    required: false
+    default: v3.5.1
 runs:
   using: composite
   steps:
diff --git a/ct.sh b/ct.sh
index 6b400c2..3ad0d9b 100755
--- a/ct.sh
+++ b/ct.sh
@@ -4,7 +4,7 @@ set -o errexit
 set -o nounset
 set -o pipefail
 
-DEFAULT_CHART_TESTING_VERSION=v3.5.0
+DEFAULT_CHART_TESTING_VERSION=v3.5.1
 
 show_help() {
 cat << EOF