diff --git a/.github/workflows/autofix.yml b/.github/workflows/autofix.yml
index 234c859b8..d8f81150a 100644
--- a/.github/workflows/autofix.yml
+++ b/.github/workflows/autofix.yml
@@ -15,7 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      - uses: install-pinned/pyupgrade@847ef2b8aa35a3817372540b887f4130d864d6b7
+      - uses: install-pinned/pyupgrade@423622e7c2088eeba495a591385ec22074284f90
       - name: Run pyupgrade
         run: |
           shopt -s globstar
diff --git a/mitmproxy/optmanager.py b/mitmproxy/optmanager.py
index 32d448323..5fa10a787 100644
--- a/mitmproxy/optmanager.py
+++ b/mitmproxy/optmanager.py
@@ -611,5 +611,5 @@ def save(opts: OptManager, path: str, defaults: bool = False) -> None:
     else:
         data = ""
 
-    with open(path, "wt", encoding="utf8") as f:
+    with open(path, "w", encoding="utf8") as f:
         serialize(opts, f, data, defaults)