Hi Adrian,
When I try apt install gluu-server=4.1.0~bionic, I get an error: not found.
gluu-admin@sissadrisgluuvmaedv:~$ sudo su
root@sissadrisgluuvmaedv:/home/gluu-admin# echo "deb https://repo.gluu.org/ubuntu/ bionic main" > /etc/apt/sources.list.d/gluu-repo.list
root@sissadrisgluuvmaedv:/home/gluu-admin# curl https://repo.gluu.org/ubuntu/gluu-apt.key | apt-key add -
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 3112 100 3112 0 0 1451 0 0:00:02 0:00:02 --:--:-- 1450
OK
root@sissadrisgluuvmaedv:/home/gluu-admin# apt update
Hit:1 http://azure.archive.ubuntu.com/ubuntu bionic InRelease
Get:2 http://azure.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:3 http://azure.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Get:4 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Ign:5 https://repo.gluu.org/ubuntu bionic InRelease
Hit:6 https://repo.gluu.org/ubuntu bionic Release
Fetched 252 kB in 1s (186 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
5 packages can be upgraded. Run 'apt list --upgradable' to see them.
root@sissadrisgluuvmaedv:/home/gluu-admin# apt install gluu-server=4.1~bionic
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Version '4.1~bionic' for 'gluu-server' was not found