I used htaccess to redirect my a.php?x=aaa&y=bbb to /subdir/aaa-bbb.htm. However, after fixing some errors I needed to change that rule to redirect a.php?x=aaa&y=bbb to /subdir/aaa-bbb.htm/100.
How can I tell search engines that all htm files in /subdir/ have changed to /subdir/*.htm/100?