For our customers running IBM’s AIX operating system, IBM has recently announced the end of support (end of life) date for AIX 5.3. It is April 30, 2012. This means that those running AIX 5.3 as an operating system will no longer be able to get software support for operating system issues after that date. Please see the attached link for details from IBM.
http://www-01.ibm.com/software/support/aix/lifecycle/index.html