That is the recommendation, but if you are feeling adventurous, you can re-use the existing workspace after deleting the com.adobe.flexbuilder.codemodel folder in workspacedir/.metadata/.plugins/
Thanks for the reply. No - I'm not feeling adventurous.
Minimally Adobe should make it crystal clear during a point release upgrade process that if the upgrade proceeds, it will break existing workspaces. This allows someone to STOP the process if they don't want to do the subsequent work involved migrating the workspaces. It will take me hours of work to create new workspaces and reconfigure my version control repositories. Not cool.
I would like to know what the possible symptoms are if you don't switch to a new workspace.
I was using the 4.5 workspace for some time when working with 4.5.1. There was no apparent malfunctioning of the system. Then I tried to switch to a new workspace, described by the recommendations. But that broke my svn settings and I couldn't recover that. So I switched back to the original 4.5 workspace. Now FB is acting very slowly as soon as I launch a debug session of my AIR application and it never recovers from that, even if I close the AIR application. I don't know if that is related to the workspace issue. I started building a mobile app for the first time yesterday, so perhaps it's related to that.
Is it possible to manually update settings in configuration files, so I don't have to switch to a new workspace?
Some possible symptoms:
1. You don't see Apple iOS in your target platforms even though you are on 4.5.1.
2. Code hinting and syntax highlighting may stop working.
3. Export release of mobile apps (non-Android) may fail without an error message.
Of course, ideally, you shouldn't see any of this happen.
But the important point is: QE tested only on new workspaces. So we don't know of bugs that may or may not be described above.