diff --git a/Dockerfile b/Dockerfile
index 6abb497..fe64a5f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -112,7 +112,7 @@ COPY --from=php-build /usr/local/lib/php /usr/local/lib/php/
 COPY --from=php-build /usr/local/include/php /usr/local/include/php/
 COPY --from=php-build /usr/local/bin /usr/local/bin/
 
-ARG COMANAGE_REGISTRY_VERSION
+ARG COMANAGE_REGISTRY_VERSION=3.1.1
 ARG COMANAGE_REGISTRY_SRC_URL=https://github.com/Internet2/comanage-registry/archive/${COMANAGE_REGISTRY_VERSION}.tar.gz
 ENV COMANAGE_REGISTRY_VERSION ${COMANAGE_REGISTRY_VERSION}