diff --git a/lib/shared-functions.sh b/lib/shared-functions.sh
index e720b3f..b1beaac 100644
--- a/lib/shared-functions.sh
+++ b/lib/shared-functions.sh
@@ -10,7 +10,7 @@ function read_config() {
 
 function read_image_version() {
   IMAGE_VERSION="$(head -n 1 "$TOOLKIT_ROOT/config/version")"
-  if [[ ! "$IMAGE_VERSION" =~ ^([0-9]+)\.[0-9]+\.[0-9]+(-RC)?(-with-texlive-full)?$ ]]; then
+  if [[ ! "$IMAGE_VERSION" =~ ^([0-9]+)\.[0-9]+\.[0-9]+(-RC[0-9]*)?(-with-texlive-full)?$ ]]; then
     echo "ERROR: invalid version '${IMAGE_VERSION}'"
     exit 1
   fi