What is Essbase
Oracle Essbase is a multidimensional database management system (MDBMS) providing a multidimensional business analytics platform. It is commonly used for budgeting, forecasting, and planning in enterprise environments.
What is Essbase 11g
Essbase 11g is the old version of Oracle Essbase where the latest patchset is 184.108.40.206
This is the latest On-Prem Essbase version available before Essbase 21c
The Premier support of Essbase 11g ended in Dec 2021. The extended support for Essbase 11g is available til Dec 2024
Essbase 11g also comes with an EPM 11.2 stack and you dont need to purchase the extended support if your EPM 11.2 support is licenced to use
What is Essbase 21c
Essbase 21 is the latest version of Essbase and it is both available for OCI and On-Prem.
More details can be find on below link
Difference between Essbase 11g and Essbase 21c
Here are the major differences between them which you should be aware of