diff --git a/renderd7.hpp b/renderd7.hpp
index eadd9b7..0b0daa6 100644
--- a/renderd7.hpp
+++ b/renderd7.hpp
@@ -21,6 +21,7 @@
 #include "parameter.hpp"
 #include "thread.hpp"
 #include "ini.hpp"
+#include "stringtool.hpp"
 
 #define RENDERD7VSTRING "0.6.10"
 #define CHANGELOG "0.6.10: rewrite Threadsystem, Improve framerate/n0.6.02: Fix Code in lang.hpp\nadd Draw Text Left Function.\nadd changelog\n0.6.01: add Threading system."