diff --git a/Makefile b/Makefile
index 564cd56..03bbdc4 100644
--- a/Makefile
+++ b/Makefile
@@ -22,6 +22,8 @@ purge: clean
 
 selfex: purge
 	@echo "Creating the self-extractible setup program... "
+	@cp ./src/msspec/version.py ./src/msspec/version.py.bak
 	@echo "__version__ = \"$(VERSION)\"" > ./src/msspec/version.py
 	$(MAKESELF) --license "$(LICENSE)" ./src $(SETUPFILE) "Python MsSpec"  ./install.sh
+	@mv ./src/msspec/version.py.bak ./src/msspec/version.py