What's the equivalent of "find -mmin" in HP-UX?

I created a script to check XML file available in the folder for more than four hours. If the XML is not processed for more than four hours then I need to send a mail for that I used the below find command but the mmin+240 is not working. Is there is any option to used instead of mmin. Please help on this.

 find $OFILEPO/*.xml  -mmin+240  -exec ls -ltr {} + | wc -l

when I execute the above find command with mmin got the below error.

         **find: bad option -mmin
          0
         $ uname -a
          HP-UX** 

I think mmin is AIX command. Please suggest for HP_UX Thanks in Advance

According to the man page hpux 10.20 - find (1), your implementation of find doesn't support the -mmin option.

The closest equivalent would be -mtime

-mtime n True if the file has been modified in n days.

Similar questions (Find files modified within one hour in HP-UX, how to find files modified in the last hour?) suggest creating a "reference" file with touch -mt $time and using find -newer.

Quoting the second link, you could do:

Create a temp file using the 'touch' command, such that the modification time is one hour in the past. For example:

# date +%m%d%H%m 06261006
# touch -mt 06260906 /tmp/tdate
# ll /tmp/tdate
-rw-r--r-- 1 root root 0 Jun 26 09:06 /tmp/tdate

Then run 'find' with the '-newer' switch, taking advantage of this file:

find /mnt -newer /tmp/tdate -type f -xdev -exec ll {} \;