As you know Oracle has new naming convention. Before start Let us check current Release and Support Timelines.
Now here is the details
Oracle Database Release Roadmap
There are two types of Oracle Database releases: Long Term Release and Innovation Release.
- Long Term Release:
Oracle Database Long Term Releases are ideal for use cases that benefit from less frequent upgrades to newer releases. Long Term Releases offer the highest level of stability and the longest length of error correction support. These releases have 5 years of Premier Support followed by 3 years of Extended Support. When combined with Extended Support, customers typically have almost 4 years to upgrade from one Long Term Release to the next Long Term Release.
- Innovation Release:
In between Oracle Database Long Term Releases, Oracle delivers Oracle Database Innovation Releases that include many enhancements and new capabilities which will also be included in the next Long Term Release. Innovation Releases are designed to enable customers to continuously use leading-edge technologies to rapidly develop or deploy new applications or augment existing applications. Support for Innovation Releases includes 2 years of Premier Support, but there is no Extended Support. Production workloads can be deployed on Innovation Releases if upgrading within 2 years to a newer release is factored into the deployment plan.
To help you plan ahead, below is a visual roadmap that captures Oracle Database Releases from 11.2 onward, showing the lifetime support stages (Premier, Extended) and the Error Correction windows for each release. Note, not all releases are eligible for Extended Support (i.e. 12.2.0.1, 18c).
Here is the convention:
12.2.0.2 -> 18.1
12.2.0.3 -> 18.2
12.2.0.4 -> 18.3
Let us see this in the graph
For more details please check Release Schedule of Current Database Releases (Doc ID 742060.1)