diff --git a/tagging/taggers.py b/tagging/taggers.py
index 0f53827e..06eb8cac 100644
--- a/tagging/taggers.py
+++ b/tagging/taggers.py
@@ -1,6 +1,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
-from datetime import datetime
+import datetime
 
 from docker.models.containers import Container
 
@@ -42,7 +42,7 @@ class SHATagger(TaggerInterface):
 class DateTagger(TaggerInterface):
     @staticmethod
     def tag_value(container: Container) -> str:
-        return datetime.utcnow().strftime("%Y-%m-%d")
+        return datetime.datetime.now(datetime.UTC).strftime("%Y-%m-%d")
 
 
 class UbuntuVersionTagger(TaggerInterface):
diff --git a/tagging/write_manifest.py b/tagging/write_manifest.py
index 16a053c5..ca7b0e03 100755
--- a/tagging/write_manifest.py
+++ b/tagging/write_manifest.py
@@ -17,7 +17,7 @@ from tagging.manifests import ManifestHeader, ManifestInterface
 LOGGER = logging.getLogger(__name__)
 
 # We use a manifest creation timestamp, which happens right after a build
-BUILD_TIMESTAMP = datetime.datetime.utcnow().isoformat()[:-7] + "Z"
+BUILD_TIMESTAMP = datetime.datetime.now(datetime.UTC).isoformat()[:-13] + "Z"
 MARKDOWN_LINE_BREAK = "<br />"