diff --git a/code/datums/callback.dm b/code/datums/callback.dm
index 03d25f1d8f1..30cca6fd49c 100644
--- a/code/datums/callback.dm
+++ b/code/datums/callback.dm
@@ -109,6 +109,12 @@
 	if (!object)
 		return
 
+#if DM_VERSION <= 514
+	if(istext(object) && object != GLOBAL_PROC)
+		to_chat(usr, "[object] may be an external library. Calling external libraries is disallowed.", confidential = TRUE)
+		return
+#endif
+
 	var/list/calling_arguments = arguments
 	if (length(args))
 		if (length(arguments))
@@ -146,6 +152,12 @@
 	if (!object)
 		return
 
+#if DM_VERSION <= 514
+	if(istext(object) && object != GLOBAL_PROC)
+		to_chat(usr, "[object] may be an external library. Calling external libraries is disallowed.", confidential = TRUE)
+		return
+#endif
+
 	var/list/calling_arguments = arguments
 	if (length(args))
 		if (length(arguments))