Installation of major versions, maintenance releases, and patches
There is a difference when installing Oracle software, depending on whether it is a major release, maintenance release, or some sort of patchset. A new major release, for example, will go from 10.x to 11.x. A maintenance release is the second set of numbers, for example, going from 11.1 to 11.2. Review Chapter 2, Maintaining Oracle Standards, for the numbering convention for Oracle releases and some recommendations related to installing patchsets.
If you are planning to do a release upgrade, either major or maintenance, then install the newer version in a new
ORACLE_HOME. Remember to set the environmental variable
ORACLE_BASE. Which version should you install? ...