Rather a read the documentation for the upgrade from version 4 to 5 ;)))))
See here: http://www.advancedcustomfields.com/resources/updates/upgrading-v4-v5/
The relevant part:
Changes to Options Pages
Previously, the default Options page was added automatically on activation of the Options Page add-on. Now that the Options Page functionality is built into ACF PRO, this will no longer be an automatic process, and the default Options Page will need to be added manually by adding this code to your functions.php file:
acf_add_options_page();
It is good practice to wrap this inside a function_exists if statement and above any defined sub pages like so:
if(function_exists('acf_add_options_page')) {
acf_add_options_page();
acf_add_options_sub_page('Header');
acf_add_options_sub_page('Footer');
}
Best regards Ralf
