Upgrading from Application Server 7.x: You can perform only a side-by-side upgrade, which involves installing the source application server installation and the target installation on the same machine, under different install locations. Before upgrade, you need to:
Upgrading from Application Server 8.x EE: You can perform a side-by-side upgrade or an in-place upgrade. Before upgrade, you need to check if any of the keystore or certificate databases have any other password other than changeit. You need to change all those passwords to changeit. You can use the keytool utility for the JKS databases and the certutil utility for the NSS databases.
Failure to change the keystore or certificate database passwords could result in the Upgrade Tool certificate transfer process being aborted abnormally.