WordPress 4.9 was released just few hours ago. It is the second and last major WordPress release of 2017 with some exciting new features and enhancements.
Custom Template files wont detect after i have updated to WordPress 4.9
Clear file cache, WordPress 4.9
A plugin to make it easy for theme developers to clear the new file cache on WordPress 4.9.
I believe 4.9.1 will have an update so the file cache is disabled when WP_DEBUG is set to true. But in the meantime, you can use this plugin.
How To Use
Download this PHP file.
Put PHP file in “wp-content/plugins” folder.
Activate plugin under “Plugins”.
Use “Clear File Cache” button in the top admin bar.
CLICK HERE TO DOWNLOAD THE PLUGIN: WP-Clear-File-Cache-master