Oracle has just changed their product life cycle support for their database technology especially Oracle 12cR2 !
Per Oracle ….As a one-time exception, Oracle will provide Limited Error Correction at no additional charge, for a period of 16 months after Premier Support Error Correction ends. Limited Error Correction will be in place from December 1, 2020 until March 31, 2022
The strategy is to give Oracle customers the time to upgrade to 19c (which is the stable release).
So far, 18c premier support ends June 2021 …..and 19c premier support ends March 2023
In my opinion this was too late from Oracle since many organizations were shooting for 18c for sometime in their landscape upgrades …..so this means basically any footprint of 18c in your landscape will require another upgrade to 19c !
its clear 12cR2 is a stable release compared to 18c, and even many other Oracle software solutions were late to be compatible with 18c !