diff --git a/luametalatex-firstcode.lua b/luametalatex-firstcode.lua
index 2ba8b06..6f7ce8d 100644
--- a/luametalatex-firstcode.lua
+++ b/luametalatex-firstcode.lua
@@ -244,11 +244,14 @@ token.luacmd("Umathcodenum", function(_, scanning)
   end
 end, "force", "global", "value")
 
-for i=0x30,0x39 do
-  tex.setmathcode(i, 7, 0, i)
-end
+if status.ini_version then
 
-for i=0x41,0x5A do
-  tex.setmathcode(i, 7, 1, i)
-  tex.setmathcode(i+0x20, 7, 1, i+0x20)
+  for i=0x30,0x39 do
+    tex.setmathcode(i, 7, 0, i)
+  end
+
+  for i=0x41,0x5A do
+    tex.setmathcode(i, 7, 1, i)
+    tex.setmathcode(i+0x20, 7, 1, i+0x20)
+  end
 end