Once PHP upgrade to the new version they possibly depreciate some functions.
If you are using any such functions in your site after setting to the new version you will notice the error mentioned below.
Deprecated: Function password_hash() is deprecated in
In order to disable this warning, you have to add the below code in your website index file, if you are using bootstrap then you have to update the bootstrap file.
error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED);
