NSA325v2 - PHP upgrade

Perhaps I've not explained myself well enough .... 

I want to do some web page development using PHP, mySQL jQuery and all that jazz. I have an  NSA325v2 which can run a web server. I use it for some databases, but using PHPmaker. I want to develop my own web pages,but the 325v2 runs version 4 (?) PHP, an old version of myPHPAdmin (4.1.14.3) and mySQL version 5.1.72.

I want to run mariadb, php7 etc. I tried phpmyadmin version 4.9.1, but it demanded mysqli extensions that I can't find a package for.

What are the limits of installing the newer versions of mySQL, PHP etc?