Standard Upgrade Procedure
This chapter describes the standard upgrade procedure which is used when minimizing downtime and ensuring that persisted data is retained. The Standard upgrades must generally be performed stepwise, i.e. to the next consecutive main or minor version, but for this version there is an exception and you can upgrade directly to 9.1 from 8.3.
Read the Documentation
Ensure to read through all the documentation for the Standard Upgrade Procedure and check out the Release Notes for 9.x for Important information and Known Issues before proceeding with the Upgrade.