Don’t let tedious configuration get in the way of building great apps.
If any of your modules or manifests rely on this behavior, you’ll need to adjust them before you upgrade.
In fact, cookies as storage have now been removed and you must always use some kind of server-side storage engine, with the file-system being the default option.
The Session Class now utilizes PHP’s own mechanisms for building custom session handlers, which also means that your session data is now accessible via the superglobal (though, we’ve kept the possibility to use it as “userdata”, like you’ve done until now).
There is however an important limitation to note: all the shared database tables will not be updated in the slaves zones.
This means that new user accounts, password changes, new ACL rules, etc. Read the The recommended procedure to upgrade two Open Nebulas configured in HA is to follow the upgrade procedure in a specific order.