cdn.install | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/cdn.install b/cdn.install
index 42816be..ea95d92 100644
--- a/cdn.install
+++ b/cdn.install
@@ -34,3 +34,9 @@ function cdn_update_8002() {
 function cdn_update_8003() {
   \Drupal::configFactory()->getEditable('cdn.settings')->set('scheme', '//')->save();
 }
+
+/**
+ * Force container & cache rebuild upon upgrading from 8.x-3.x to 4.x.
+ */
+function cdn_update_9401() {
+}