Prepare release 0.4.0-incubating
diff --git a/Makefile b/Makefile
index 79a9c00..aba6b2a 100644
--- a/Makefile
+++ b/Makefile
@@ -20,7 +20,7 @@
      dev-binder \
      audit audit-licenses
 
-BASE_VERSION?=0.4.0.dev1
+BASE_VERSION?=0.4.0
 VERSION=$(BASE_VERSION)-incubating
 COMMIT=$(shell git rev-parse --short=12 --verify HEAD)
 ifeq (, $(findstring dev, $(VERSION)))