Update php version?

Question

PHP

Tell me, my site works on php 5.2 on hosting, it is possible to enable, for example, php 7.
If this is done, will the site work? Or do I need to change something on the site to upgrade to the new version?

Answer 1

If this is done, will the site work?

If outdated or disabled functionality is used, the places on your site where they are used will be broken.
Of course you need.

Answer 2

Migrating php5.x to php7.x . "Backwards incompatible changes" is something you need to consider and eliminate from your code if you plan to upgrade to a more recent version.

Answer 3

It is correct to make a test server for such things (usually a subdomain of the main site, often free. for good, test all the functionality of the site.
Basically, when upgrading the php version, backward compatibility is preserved i.e. What works on the old version should also work on the new one. But there are also incompatible changes, to which Oleg gave a link .