Didn't ask about kit configuration when upgrading

I'm testing a 5.6.0 package, freshly installed.
Qt Creator offers me the option to start "default (last sessions)"; I click it.
It starts up and my ~/.xsession-errors gets two messages:

Warning: No kit 'qt.55.gcc_64_kit' found. Continuing.
Warning: No kit 'qt.55.gcc_64_kit' found. Continuing.

I discuss with Eike Ziller, who tells me what should happen:

>> If you open a project which was configured for a kit that
>> no longer exists, you get to the kit configuration page (like when
>> opening a project for the first time), where you select the kit(s) to
>> use. That way the user is actually aware of what happens, and can
>> choose for him/herself.
>
> hmm ... I don't think I saw those dialogs.

No dialogs. It should just switch to “Projects” mode by default (one of the larger buttons in the left vertical tool bar).

I've now repeated the process from scratch to verify that, indeed, I was not dropped into Projects mode; I'm looking at the Edit view, showing the files I was looking at at the end of my last session.

I'm running Qt Creator from my home directory; it's installed under ~/test/release/Qt5.6.0/ and the project files are under ~/test/bug/. In this, ~/test/ is a symlink to /mnt/test/eddy/, where /mnt/test/ is the mount-point of a separate partition.

Qt Creator's about page claims it is based on Qt 5.5.0, not 5.6.0. It gives its own version as 3.5.0; the Qt5.6.0 I've just installed, that it comes from, is the recent beta package.