Php Warning error php_msgpack_serialize

Ever since I ran a recent apt-get upgrade I get the following error e-mailed to me. Does anyone know how to correct this error? I can’t seem to find a solution.

PHP Warning: PHP Startup: Unable to load dynamic library ‘/usr/lib/php/20131226/’ - /usr/lib/php/20131226/ undefined symbol: php_msgpack_serialize in Unknown on line 0

Since I’m using redis caching I wonder if I should just remove memcached entirely, I don’t believe anything should be using it, would this cause any issues?