CodeIgniter can be used or abused to suit your particular requirements. It was first introduced way back January 2006, has had about 27 updates most of which are to ensure safety against hacking. Latest current stable version is 2.1.3. A Git development module is also available.
There are a "stack" of programmers available many who contribute to the user friendly forum. Wiki library or fork Gits.
CodeIgiter follows the MVC principle, is quick to get started, robust. Numerous databases are simplified and can be easily switched by using the Database Module and also their Active Record Class. All data is validated and "cleaned" unobtrusively in the background before any update or insertions are made thus making robust programming easier.
Their very small footprint makes it very fast. Updates and swapping versions is usually just a case of re-directing the index.php -> $system variable.
All in all it is a very robust, mature and structure framwork which certainly is far easier to follow than other programmer's spaghetti structure.
NB I had to search for the collective noun for "programmers" and besides stack, other favourite are collection, fork, heap, module, nerd...