diff --git a/4dm.h b/4dm.h
index d2c04a1..c21d465 160000
--- a/4dm.h
+++ b/4dm.h
@@ -1 +1 @@
-Subproject commit d2c04a1027887e83ff892f6c60cd12785a8f387a
+Subproject commit c21d4659a4119bca4b25313ca46f1043532cdc4b