The product name and level number identify a software product. The level of a software product in AIX Version 4.3 is defined as vv.rr.mmmm.ffff, where:
For example, 04.01.0000.0000 is a software product level number, and 04.01.0001.0032 is a software product update level. It is not necessary to include the leading zeroes in the version, release, modification level, and fix level fields of the level. Level 04.01.0000.0000 can also be written as 4.1.0.0.
The vv.rr.mmmm.ffff part of the level field is what is checked to find if the level being installed is later than that on the system. These fields increase for each subsequent release of a product. The higher precedence of the four fields goes from left to right (that is, level 4.2.0.0 is a later level than 4.1.3.4).