diff --git a/VERSION b/VERSION
new file mode 100644
index 000000000000..4d1ef1b5b42c
--- /dev/null
+++ b/VERSION
@@ -0,0 +1 @@
+RIOT_VERSION = 2021.10
diff --git a/makefiles/docker.inc.mk b/makefiles/docker.inc.mk
index b5bdb10f1292..0bae5f262774 100644
--- a/makefiles/docker.inc.mk
+++ b/makefiles/docker.inc.mk
@@ -1,4 +1,4 @@
-export DOCKER_IMAGE ?= riot/riotbuild:latest
+export DOCKER_IMAGE ?= riot/riotbuild:2021.10
 export DOCKER_BUILD_ROOT ?= /data/riotbuild
 DOCKER_RIOTBASE ?= $(DOCKER_BUILD_ROOT)/riotbase
 # List of Docker-enabled make goals