This document concentrates on using the latest releases of E1 Tools, E1 Applications (Apps), and OEE (Oracle Enterprise Edition database which is installed on the Development Client). These releases are documented in Oracle's Certifications. In some cases, it is possible to mix old or new releases of E1 with various versions of the OEE database. For example, an Apps 9.1 package can be installed on a computer with OEE 12c or 11gR2 installed.