CodeIgniter was given a new lease of life with V3 and we are more than happy to embrace this platform for you. It is a light-weight framework which is very easy to maintain and well supported. Within the community it does have a slight `past its time` label which is quite unfair and there are many good reasons to use CI.
As we are framework agnostic, CI is on the list as an excellent PHP | MySQL platform. If you have an existing web-site based on CI which needs a fresh coat or this is just your platform of choice then we are more than happy to assist. Moving away from CI to, say, Laravel isn't really justified unless you are running a very old version as migration to the latest version with PHP 7 is quite straightforward.
By way of an example, check out the Web-Site Maps on the demo page. Believe it or not this site is actually a CI application, but by dint of its use of MapBox [a JS map system like Google Maps] it is really written as a SPA. Another and more common example is our simple CMS based web-site, where you serve up Content Management Pages, sort of Wordpress-style. These systems are very easy to install - a day or two - and while still very MVC in their structure, they look and behave more like applications.
As of 2019, CI V4 is due for release which is in the main more of a modern framework structure update and insists on PHP 7+