diff --git a/rbutil/rbutilqt/irivertools/irivertools.h b/rbutil/rbutilqt/irivertools/irivertools.h
index 8ded0807f8..b1fce826c1 100644
--- a/rbutil/rbutilqt/irivertools/irivertools.h
+++ b/rbutil/rbutilqt/irivertools/irivertools.h
@@ -30,8 +30,8 @@
 #define ESTF_SIZE 32
 
 struct sumpairs {
-    char *unpatched;
-    char *patched;
+    const char *unpatched;
+    const char *patched;
 };