Change File Extension

I have always used .htm instead of .html
I just upgraded to 4.7.3 and edited the file:
app/addons/seo/init.php
fn_define('SEO_FILENAME_EXTENSION', '.htm');
to change it. It has always worked in the past but not this time.
Is there somewhere else to make my files end with .htm instead of .html?

I have just tested it on the local installation and it works correctly.

Hmm. CS-Cart also said I was correct on the fix, but to delete my var/cache folder. I did do that before I asked and it wasn't fixed. Went to different browsers but the pages still ended in html.

Going to wait now till I have time to try again. Had all wrong extensions for about an hour and a half where people clicking through from Google (or anywhere) would land on a 404 error page.

I was able to revert back to previous version to fix it.

Thanks for checking on a local install. At least I know it was the correct way.