What sort of functionality will I miss out on?

[wobbly]

I'm currently running

PHP Version 4.4.7 & Mysql 4.1.22-standard.

Will I be able to upgrade to 3.7 and upwards without upgrading and if so what sort of functionality will I miss out on?

orry for asking the question but I searched about and came up with nothing.

[Zachery]

You can use that just fine, there is no missing functionality.

[wobbly]

Fantastic.

Many thanks for your prompt reply.