diff --git a/mods/ITEMS/mcl_armor/register.lua b/mods/ITEMS/mcl_armor/register.lua
index 2c26b50d4..be9e75267 100644
--- a/mods/ITEMS/mcl_armor/register.lua
+++ b/mods/ITEMS/mcl_armor/register.lua
@@ -79,7 +79,7 @@ mcl_armor.register_set({
 	},
 	toughness = 2,
 	craft_material = "mcl_core:diamond",
-	_mcl_upgradable = true
+	_mcl_upgradable = 1
 })
 
 mcl_armor.register_set({