diff --git a/.github/workflows/update.yaml b/.github/workflows/update.yaml
index d15119e..dfddbf1 100644
--- a/.github/workflows/update.yaml
+++ b/.github/workflows/update.yaml
@@ -19,7 +19,7 @@ jobs:
     # of simplejson (https://github.com/matrix-org/python-canonicaljson/pull/25/files)
     - uses: actions/setup-python@v4
       with:
-        python-version: 'pypy3.9'
+        python-version: 'pypy3.10'
     - name: Update data
       run: |
         mkdir -p advisories
diff --git a/generate.py b/generate.py
index 785c567..e7695c9 100644
--- a/generate.py
+++ b/generate.py
@@ -5,7 +5,7 @@ import markdown
 import json
 import canonicaljson
 import urllib.request
-from datetime import datetime,UTC
+from datetime import datetime
 import copy
 import os
 import re
@@ -29,7 +29,7 @@ def last_modified_date(file):
         .decode("utf-8")
         .strip()
     )
-    return datetime.fromtimestamp(p, UTC)
+    return datetime.utcfromtimestamp(p)
 
 
 def created_date(file):