diff --git a/site/app.yaml b/site/app.yaml
index 8ccbde2..0687482 100644
--- a/site/app.yaml
+++ b/site/app.yaml
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-runtime: go121
+runtime: go123
 
 default_expiration: "1m"