Renamed old template files used instead of new

I edited a custom template file called landingpage.php, first saving the original as landingpage-old.php. The edits weren’t showing up in the WP front-end. I eventually noticed, in the Dashboard: Appearance->Editor that the old file, landingpage-old.php, appeared in the file list. Renaming the file landingpage.php.old solves the problem.