diff --git a/Dockerfile.9-dev b/Dockerfile.9-dev
index ffde73d..dcf11b6 100644
--- a/Dockerfile.9-dev
+++ b/Dockerfile.9-dev
@@ -16,7 +16,7 @@ ARG SHELL_OPTS="set -e -o pipefail"
 
 ARG SERVICE_PORT=""
 ARG EXPOSE_PORTS=""
-ARG PHP_VERSION="system"
+ARG PHP_VERSION="7.4"
 ARG NODE_VERSION="system"
 ARG NODE_MANAGER="system"