diff --git a/headers/os/mail/E-mail.h b/headers/os/mail/E-mail.h
index d3c024450c..72662586c4 100644
--- a/headers/os/mail/E-mail.h
+++ b/headers/os/mail/E-mail.h
@@ -30,7 +30,6 @@ struct entry_ref;
 #define B_MAIL_ATTR_CONTENT		"MAIL:content_length"	// int32
 #define B_MAIL_ATTR_READ		"MAIL:read"				// int32
 
-#define R5_COMPATIBLE 1
 
 // read flags
 enum read_flags {
diff --git a/headers/private/mail/mail_util.h b/headers/private/mail/mail_util.h
index 293bb4a9da..25247c1522 100644
--- a/headers/private/mail/mail_util.h
+++ b/headers/private/mail/mail_util.h
@@ -13,6 +13,9 @@
 #include <E-mail.h>
 
 
+#define R5_COMPATIBLE 1
+
+
 class BString;