diff --git a/makefile b/makefile
index e24aa0c..18c033a 100644
--- a/makefile
+++ b/makefile
@@ -8,7 +8,7 @@ version:
 version-%: OLDVERSION:=$(shell python setup.py --version)
 version-%: NEWVERSION=$(subst -,.,$*)
 version-%: 
-	sed -i -e s/$(OLDVERSION)/$(NEWVERSION)/ $(VERSION_FILE)
+	sed -i '' -e s/$(OLDVERSION)/$(NEWVERSION)/ $(VERSION_FILE)
 	git ci setup.py -m"bump version to $*"
 
 lint: