Aqui les dejo el post que escribió Joel Kallman sobre la secuencia de la actualización:
One of the features of Oracle Application Express 5.1 is a "reduced downtime upgrade" (thanks to Christian Neumueller-Oracle). This upgrade will happen in multiple phases:
Phase 1 (beginning at 0600 EST, 1100 UTC): Installation of APEX 5.1 software with translations. This won't be visible to end users
- Phase 2 (beginning at roughly 0800 EST, 1300 UTC): Migration begins. All APEX applications will continue to run, but you will not be able to change any application definitions or underlying APEX metadata (including saved Interactive Reports).
- Phase 3 (beginning at 2100 EST, 0200 UTC): Complete outage. https://apex.oracle.com will not be accessible.
- Phase 4 (estimated between 2200 EST and 2300 EST, 0300 UTC and 0400 UTC): https://apex.oracle.com will be fully accessible again. Non-critical log information will be migrated forward to APEX 5.1, but in the background.
Beginning Thursday evening EST, December 15, 2016, you will not be able to request or provision new workspaces on apex.oracle.com, until the upgrade to APEX 5.1 is complete.