First off, a sound update strategy in my experience is to update when you must, not update when you can. Every update introduces some risk and if you don't have to take this risk then let the system alone.
Having said this: it seems you are not quite aware what an APAR or a fix is. You might want to read
this article to learn about what fixes, APARs, maintenance/technical levels, etc. are. You might also want to read
this thread for some further information.
There are some threads pinned in the top of the forum with some useful links, IBMs Fix Central should be among them. There you can download all the IBM fixes.
I hope this helps.
bakunin