Xen 4.6 on Debian Stretch

I wanted to update to a newer Xen-Version, so I decided to upgrade the Debian host system to Stretch (current testing). It contains Xen 4.6 and a newer kernel. First you need to update your /etc/apt/sources.list. Enter this (or choose your local mirror):
deb http://ftp.debian.org/debian/dists/stretch/ stretch main
Perform the upgrade
apt-get update && apt-get upgrade
Check that all packages are updated correct and there are no (non-broken) packages left for update.
Check that you’ve the new Xen hypervisor installed:
apt-get install xen-hypervisor-4.6-amd64 xen-utils-4.6
Check that you get a new 4.x kernel, search for linux-image and install a 4.x one (4.6.0 in my case):
apt-get install linux-image-4.6.0-1-amd64
Make sure the kernel is properly installed, reboot into the new kernel.

I had one problem with this. The console did not work:
xl console hostname
xenconsole: Could not open tty `/dev/pts/1': No such file or directory

xenconsole: Could not read tty from store: No such file or directory

Check if the stated device is present:
root@hostname ~ # ls -ld /dev/pts/
5 ptmx

No, it’s not.
Call /usr/lib/xen-4.6/bin/xenconsoled
Now it’s fixed:
root@hostname ~ # ls -ld /dev/pts/*
crw--w---- 1 root tty 136, 0 Jul 19 14:59 /dev1/pts/0
crw--w---- 1 root tty 136, 1 Jul 19 14:59 /dev/pts/1

Wired Xen error

I was trying to migrate a VM from an older version of Xen to Xen 4.6. The console did not work after boot, it showed the login prompt, but it was not possible to type. I saw these error messages:

[ 24.684852] genirq: Flags mismatch irq 8. 00000000 (hvc_console) vs. 00000000 (rtc0)
[ 24.684860] hvc_open: request_irq failed with rc -16.

In hvc console not working on 4.4.0 guest I found the workaround to set 2 vpus for the VM. This worked.