MySQLi version mismatch

Example issue:

Message: mysqli::real_connect(): Headers and client library minor version mismatch. Headers:50550 Library:100029

Sounds like server issue. PHP and MySQL versions not compatible.

Try this solution:

If this is localhost try with:

For localhost, you can for example (Windows guide):
Install portable XAMPP Version 5.6.3
Create folder in (depends where you install xampp): C:\xampp\htdocs\mywebsite