Exadata Database Machine supports Oracle Database 12c Release 1.

Database Machine can run a mixture of 11.2 and 12.1 databases.

All new features of Oracle Database 12c Release 1 are supported.

Exadata Storage Server version 11.2.3.2.1 (or later) required

Full offload support:

Smart scan

Fast file creation

Fast incremental backup

Full IORM support:

Non-CDB

Multitenant architecture

Support for Mixed Database Versions

New CELLSRV architecture to support mixed database versions: 11.2 and 12.1

Separate offload servers 

No additional configuration or maintenance

Cell to Cell transfer in 11.2:

Database server sends read request to Cell A

Cell 1 sends data to database server

Data is stored in the database
server memory

Database server sends data to Cell 2

Cell to Cell transfer in 12.1:

Database server sends transfer request to Cell 2

Cell 2 reads data from Cell 1

So lower network bandwidth consumption

Lower database server resource usage

Used by ASM resynchronization and rebalance operations