If you are using a old version of memcached server then its time to move. we were using the memcached-1.2.2 version and now moved to 1.4.4. We are having no issues with the latest stable version.
What is Memcached?
Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.
Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.
Memcached is simple yet powerful. Its simple design promotes quick deployment, ease of development, and solves many problems facing large data caches. Its API is available for most popular languages.
For upgradingÂ memcachedÂ just kill the running process ofÂ memcachedÂ server and .Just install it with the latest version with the same location where u installed the old version, thats all, Now you can start your server.
Also see How to Install Memcached