I love how campaign reports in Sendy show the countries that users are in when they open an email. I wanted to have the country code inside the subscribers table updated each time a subscriber opens an email so I can have updated segments, which I've created by country.
I'm an amateur coder, and created a PHP file to accomplish this goal.
Download it here: https://drive.google.com/open?id=1h2BgHJLNQdwJtl-5Ax0qzYk8DxAMab6B
Install it by uploading it into your Sendy root directory.
Set a cron job to call the php file:
Command: php /your/directory/update-country.php > /dev/null 2>&1
Time Interval: */15 * * * *
Use at your own risk. It's working perfectly for me.