Graph API 2.0 is not more work because it's unavailable as of August 7, 2016:
Check this: https://developers.facebook.com/docs/apps/changelog
So, you have to update your PHP version to 5.4 or latest 7.0/7.1 And Then you can used Graph API version v2.3 to v2.9, and then follow below steps:
Login with Facebook using PHP 5.6 and latest
Pre - Requirements
- PHP version should be 5.6 or greater (7.0/1).
- The mbstring extension should be enabled.
Steps : https://www.codexworld.com/login-with-facebook-using-php/
Or
Steps : http://www.krizna.com/demo/login-with-facebook-using-php/
NOTE : Which type of code you did in application, which is not compatible with PHP 5.4 or greater? Can you update your question with that code.
Follow the following steps to upgrade your PHP version from 5.3 to 5.4/5.6
We can access the new PHP (php5.4 /php5.6) and old php (php5.x). Both are easily accessible.
Just to need to change the PHP version like below:
Download PHP5.4 From http://windows.php.net/download/#php-5.4 (Download Thread Safe) or download PHP5.6 from http://windows.php.net/download/#php-5.6 (download thread safe)
Go to PHP folder location (i.e C:\wamp\bin\php)
Create a new folder with name php5.4.42. or php5.6.30
Extract the download files and save in C:\wamp\bin\php\php5.4.42. or C:\wamp\bin\php\php5.6.30.
Copy the following files from your old PHP directory to your new PHP directory ().
php.ini
phpForApache.ini
wampserver.conf`
Open new copied php.ini file.
Update the extension_dir path in file.
Open new phpForApache.ini file.
Update the extension_dir path in file
Reboot your system.
Start wamp Server
Go to wampserver =>PHP=>Version=>PHP 5.4.42 or PHP 5.6.30`
Now running PHP5.4.42 or PHP5.6.30 or PHP7.0/1

Note: you might need to re-enable the PHP extension like CURL, Openssl etc