diff --git a/Makefile b/Makefile
index 61160bb..9cfee1a 100644
--- a/Makefile
+++ b/Makefile
@@ -46,7 +46,9 @@ all: $(ELF)
 $(OBJDIR) build:
 	mkdir -p $@
 
-$(OBJDIR)/%.o: src/%.c | $(OBJDIR)
+# VERSION is compiled into the objects, and make doesn't notice a changed flag,
+# so a new version has to rebuild them.
+$(OBJDIR)/%.o: src/%.c VERSION | $(OBJDIR)
 	$(CC) $(CFLAGS) -c $< -o $@
 
 build/client.c: client/index.html tools/embed_client.py | build
diff --git a/launcher/Makefile b/launcher/Makefile
index d782581..ceedc8f 100644
--- a/launcher/Makefile
+++ b/launcher/Makefile
@@ -18,9 +18,10 @@ FONTS := ../vendor/roboto/Roboto-Light.ttf ../vendor/roboto/Roboto-Regular.ttf
 all: package
 $(OUT):
 	mkdir -p $@
-$(OUT)/%.o: %.c | $(OUT)
+# The version is compiled in; a new one must rebuild everything that shows it.
+$(OUT)/%.o: %.c ../VERSION | $(OUT)
 	$(CC) $(CFLAGS) -std=gnu11 -c $< -o $@
-$(OUT)/main.o: main.cpp | $(OUT)
+$(OUT)/main.o: main.cpp ../VERSION | $(OUT)
 	$(CXX) $(CFLAGS) -std=c++17 -fno-exceptions -fno-rtti -c $< -o $@
 $(OUT)/qrcodegen.o: ../vendor/qrcodegen/qrcodegen.c | $(OUT)
 	$(CC) $(CFLAGS) -std=gnu11 -c $< -o $@