diff --git a/include/supported.h b/include/supported.h
index beeb89c..1ed7c0d 100644
--- a/include/supported.h
+++ b/include/supported.h
@@ -36,7 +36,7 @@
 #define INCLUDED_supported_h
 
 extern void add_isupport(const char *, const char *(*)(const void *), const void *);
-extern void change_isupport(const char *, const char *(*)(const void *), const void *);
+extern const void *change_isupport(const char *, const char *(*)(const void *), const void *);
 extern void delete_isupport(const char *);
 extern void show_isupport(struct Client *);
 extern void init_isupport(void);
diff --git a/src/supported.c b/src/supported.c
index 2f52479..6c6b33c 100644
--- a/src/supported.c
+++ b/src/supported.c
@@ -111,11 +111,12 @@ add_isupport(const char *name, const char *(*func)(const void *), const void *pa
 	rb_dlinkAddTail(item, &item->node, &isupportlist);
 }
 
-void
+const void *
 change_isupport(const char *name, const char *(*func)(const void *), const void *param)
 {
 	rb_dlink_node *ptr;
 	struct isupportitem *item;
+	void *oldvalue;
 
 	RB_DLINK_FOREACH(ptr, isupportlist.head)
 	{
@@ -123,6 +124,8 @@ change_isupport(const char *name, const char *(*func)(const void *), const void
 
 		if (!strcmp(item->name, name))
 		{
+			oldvalue = item->param;
+
 			item->name = name;
 			item->func = func;
 			item->param = param;
@@ -130,6 +133,8 @@ change_isupport(const char *name, const char *(*func)(const void *), const void
 			break;
 		}
 	}
+
+	return oldvalue;
 }
 
 void