I did… Doesn´t make any differences.
[20:52:51] openhabian@openHABianPi:~$ sudo apt-get update
Ign:1 http://repos.azulsystems.com/debian stable InRelease
Hit:2 http://raspbian.raspberrypi.org/raspbian stretch InRelease
Hit:3 http://archive.raspberrypi.org/debian stretch InRelease
Hit:4 http://repos.azulsystems.com/debian stable Release
Hit:5 https://deb.nodesource.com/node_8.x stretch InRelease
Ign:6 https://dl.bintray.com/openhab/apt-repo2 testing InRelease
Hit:7 https://dl.bintray.com/openhab/apt-repo2 testing Release
Reading package lists... Done
[20:53:09] openhabian@openHABianPi:~$ apt-get update && sudo apt-get install openhab2=2.4.0~M7-1
Reading package lists... Done
W: chmod 0700 of directory /var/lib/apt/lists/partial failed - SetupAPTPartialDirectory (1: Operation not permitted)
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
W: Problem unlinking the file /var/cache/apt/pkgcache.bin - RemoveCaches (13: Permission denied)
W: Problem unlinking the file /var/cache/apt/srcpkgcache.bin - RemoveCaches (13: Permission denied)
[20:53:24] openhabian@openHABianPi:~$