Upgrade Laravel from 5.2.45 to 7.0

I inherited a Laravel app that works fine but it's really old version (5.2.45).

What's the best way to upgrade this to something supportable? This Laravel version is incompatible with PHP 7.3 so I am stuck using an old PHP 7.0 version that is deprecated and a security risk.

Is Laravel 7.0 my best bet or should I upgrade to a different version?

PS: I'm noob on PHP, so please be as detailed as possible.

via Chebli Mohamed