diff --git a/runtime/indent/hamster.vim b/runtime/indent/hamster.vim
index b27a173..ae5c3fd 100644
--- a/runtime/indent/hamster.vim
+++ b/runtime/indent/hamster.vim
@@ -1,8 +1,14 @@
 " Vim indent file
 " Language:    Hamster Script 
-" Version:     2.0.6.0
-" Last Change: Wed Nov 08 2006 12:02:42 PM
-" Maintainer:  David Fishburn <fishburn@ianywhere.com>
+" Version:     2.0.6.1
+" Last Change: 2021 Oct 11
+" Maintainer:  David Fishburn <dfishburn dot vim at gmail dot com>
+" Download: https://www.vim.org/scripts/script.php?script_id=1099
+"
+"    2.0.6.1 (Oct 2021)
+"        Added b:undo_indent
+"        Added cpo check
+"
 
 " Only load this indent file when no other was loaded.
 if exists("b:did_indent")
@@ -14,12 +20,17 @@
 setlocal indentkeys+==~do,=~until,=~while,=~repeat,=~for,=~loop
 setlocal indentkeys+==~sub,=~endsub
 
+let b:undo_indent = "setl indentkeys<"
+
 " Define the appropriate indent function but only once
 setlocal indentexpr=HamGetFreeIndent()
 if exists("*HamGetFreeIndent")
   finish
 endif
 
+let s:keepcpo = &cpo
+set cpo&vim
+
 function HamGetIndent(lnum)
   let ind = indent(a:lnum)
   let prevline=getline(a:lnum)
@@ -52,4 +63,8 @@
   return ind
 endfunction
 
+" Restore:
+let &cpo = s:keepcpo
+unlet s:keepcpo
+
 " vim:sw=2 tw=80