I don't get a hang / crash when using old files with an updated P6, but I'm going to post the script anyway.

It will create a modified copy of .DYN file, which will be written to a file of the same name but with .FIX appended.
You'll then need to rename / move the original .DYN and rename the .FIX to .DYN

Do NOT use the modified files with an unupdated P6 (I'm sure it will confuse it or worse).