diff --git a/ci-automation/ci_automation_common.sh b/ci-automation/ci_automation_common.sh
index 488b4d6a1c..b8c80ce0f6 100644
--- a/ci-automation/ci_automation_common.sh
+++ b/ci-automation/ci_automation_common.sh
@@ -161,7 +161,7 @@ function image_exists_locally() {
 # --
 
 # Derive docker-safe image version string from vernum.
-#
+# Keep in sync with sdk_lib/sdk_container_common.sh
 function vernum_to_docker_image_version() {
     local vernum="$1"
     echo "$vernum" | sed 's/[+]/-/g'
diff --git a/sdk_lib/sdk_container_common.sh b/sdk_lib/sdk_container_common.sh
index e8fd718bff..788b0bbef1 100644
--- a/sdk_lib/sdk_container_common.sh
+++ b/sdk_lib/sdk_container_common.sh
@@ -134,7 +134,7 @@ function strip_version_prefix() {
 # --
 
 # Derive docker-safe image version string from vernum.
-#
+# Keep in sync with ci-automation/ci_automation_common.sh
 function vernum_to_docker_image_version() {
     local vernum="$1"
     echo "$vernum" | sed 's/[+]/-/g'