diff --git a/build-k4.sh b/build-k4.sh
index a483d8993ef03f377d1fdd74fecf76d4f1d6adbe..6e2e3bdb10466804663b8b424ae7487062b344ec 100755
--- a/build-k4.sh
+++ b/build-k4.sh
@@ -109,7 +109,7 @@ function run-make() {
 ##############################################################################
 
 # The current default platform
-k4_platform=x86_64-linux-gcc9-opt
+k4_platform=x86_64-linux-gcc11-opt
 k4_version=master
 bldtool=${CEPCSW_BLDTOOL} # make, ninja # set in env var