9.1.1 is out! (There's no 9.1.0, the automated releases job on GitHub starts the count at 1
)
9.0.x will still be updated weekly, at least for some time, and the updater won't update to 9.1.x. If you like 9.0.x, you can keep using it.
I updated https://vanilla-dpup.github.io/ accordingly.
Xdialog, the last user of GTK+ 2 except ROX-Filer and Sylpheed (which don't support GTK+ 3) has been replaced with @jamesbond's GTK+ 3 port.
(ROX-Filer and Sylpheed are gone in development builds of 10.x, and it's 100% free from GTK+ 2. But the 9.x series lives on, and the focus is polish and under-the-hood changes.)
apt and Synaptic are now included (they're responsible for the 16 MB increase in size):

The menu is updated automatically on package installation or removal.
@Maybe asked how to install Wine, and now it's easier than ever because 9.1.x uses the "merged /usr" directory layout like Debian and apt can be used to install 32-bit packages alongside the 64-bit ones:

This directory layout change makes 9.1.x incompatible with 9.0.x, so this update is manual.
Support for apt is not perfect, but it works well enough to install a working Xfce desktop:


And KDE works too:

PPM and pkg are still included for users who prefer them. I recommend you to treat apt like an experimental feature. (Maybe I'll remove PPM and pkg in 10.x, after apt is battle-tested enough.)
I decided to drop ISO releases and the 32-bit flavor in 9.1.x, to reduce the testing effort. If anyone wants to fork Vanilla Dpup and create a 32-bit variant or publish ISOs - feel free to do this, as long as it's clearly stated that this is a fork, spin-off, rebuild or whatever.