Personalizations are — and have always been — one of the safest and most upgradable ways to “customize” your Oracle E-Business Suite screens, both for Oracle Forms-based screens and for Oracle Application Framework-based pages. However, the upgrade from Release 11i to Release 12.1 spans many years of EBS evolution, during which time Oracle has actively been building many new features and modules. A lot has changed in Oracle E-Business Suite that may affect upgrading your personalizations from 11i to 12.1.
We have published a new note on My Oracle Support that discusses ways to evaluate your existing personalizations:
Upgrading Form Personalizations and OA Framework Personalizations from Oracle E-Business Suite Release 11i to 12.1 (Note 1292611.1)
Two distinct types of personalizations
There are two distinct types of personalizations:
OA Framework Personalization.
Both types of personalization are completely metadata-based. The personalizations are stored as data in database tables. However, because the underlying technologies (Oracle Forms and OA Framework) are very different, Forms personalizations and OA Framework personalizations are not equivalent and cannot be converted or migrated from one to the other.
To read full article – http://blogs.oracle.com/stevenChan/2011/02/personalization_upgrades_whitepaper.html