Codeigniter 3 Session not working With PHP 7.1.4

I found that the issue is with some earlier version of Codeigniter 3 and this is a bug already reported in their website.The underlying session bug has been fixed on:

• 3.1.2
• 3.1.3
• 3.1.4

So in the latest version of Codeigniter 3 this issue doesn't happen.

Solutions:

If you are already in a faulty version codeigniter consider replacing system folder with latest version's one. Version 3.1.6 at the time writing this.