diff --git a/runtime/indent/occam.vim b/runtime/indent/occam.vim
index 2979ac1..673940a 100644
--- a/runtime/indent/occam.vim
+++ b/runtime/indent/occam.vim
@@ -2,7 +2,7 @@
 " Language:	occam
 " Maintainer:	Mario Schweigler <ms44@kent.ac.uk> (Invalid email address)
 " 		Doug Kearns <dougkearns@gmail.com>
-" Last Change:	23 April 2003
+" Last Change:	2022 Apr 06
 
 " Only load this indent file when no other was loaded.
 if exists("b:did_indent")
@@ -17,6 +17,8 @@
 setlocal indentkeys=o,O,0=:
 "}}}
 
+let b:undo_indent = "setl inde< indk<"
+
 " Only define the function once
 if exists("*GetOccamIndent")
   finish