No problem...
Last year Apple released Jaguar, which was OS X version 10.2.0. Apple's version numbers always consist of three numbers separated by dots.
- The first number is the major version. In this case, 10 indicates OS X.
- The second number is incremented when major new features are added. In this case, the 2 indicates version 10.2, the third release of version 10 (after 10.0 and 10.1).
- And the third number represents interim release numbers, which are usually released to fix bugs or support new hardware. New features are not usually added. As of today, the lastest version of OS X for most people is 10.2.6, the sixth interim update.
Let's say your Jaguar install disk installs version 10.2.0. Each time Apple released a new update (10.2.1, 10.2.2, etc.) they release an incremental updater that updates your system from one release to the next. Essentially, it just installs all of the changes for that release and that release only.
However, they also post a combo updater within a few days of each release. The combo updater is larger and it includes all of the changes going back to the beginning. So if you have 10.2.0 on your disk, you can just run the combo updater to get 10.2.6 without having to run the .1, .2, .3, .4, .5, and then the .6 updates. See?
Experience with OS X has shown us that when updating from 10.2.x to 10.2.(x+1) it's more reliable to simply run the combo updater instead.
It's perfectly safe to always update with the combo updater. I've done this every time and my machine is stable as can be.
Chris