How to use memcached in phalcon, Fatal error: Class 'Phalcon\Cache\Backend\Libmemcached' not found
there is no 'Phalcon\Cache\Backend\Libmemecached' Class, just a 'Phalcon\Cache\Backend\Memche' version 1.2.6
Actually there is Phalcon\Cache\Backend\Libmemcached but it's only available from version 1.3.0. You can use 1.3.1 by building the extension manually:
git clone https://github.com/phalcon/cphalcon.git
git checkout 1.3.1
don't forget to update your devtools too.