diff --git a/Makefile b/Makefile
index 9614d43..be6ed7a 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ PROTOCOL_VERSION?=104
 
 # Windows-specific
 WIN_CXX=x86_64-w64-mingw32-g++
-WIN_CXXFLAGS=-std=c++17 -O3 #-g3 -fsanitize=address
+WIN_CXXFLAGS=-std=c++17 -O3 -DPROTOCOL_VERSION=$(PROTOCOL_VERSION) #-g3 -fsanitize=address
 WIN_LDFLAGS=-static -lws2_32 -lwsock32
 WIN_SERVER=bin/winfusion.exe