Something that always comes up when discussing Oracle versions is that I am not always sure which number is the Major Database Release and which is the Database Maintenance Release. In the Oracle documentation, the numbers are clearly described:
Oracle Release Number Format
┬ ┬ ┬ ┬ ┬
│ │ │ │ └───── Platform-Specific Release Number
│ │ │ └────────── Component-Specific Release Number
│ │ └─────────────── Fusion Middleware Release Number
│ └──────────────────── Database Maintenance Release Number
└───────────────────────── Major Database Release Number
Whereas the different numbers mean the following:
Major Database Release Number
The first numeral is the most general identifier. It represents a major new version of the software that contains significant new functionality.
Database Maintenance Release Number
The second numeral represents a maintenance release level. Some new features may also be included.
Fusion Middleware Release Number
The third numeral reflects the release level of Oracle Fusion Middleware.
Component-Specific Release Number
The fourth numeral identifies a release level specific to a component. Different components can have different numbers in this position depending upon, for example, component patch sets or interim releases.
Platform-Specific Release Number
The fifth numeral identifies a platform-specific release. Usually this is a patch set. When different platforms require the equivalent patch set, this numeral will be the same across the affected platforms.