I need to upgrade my ubuntu 16.04 LTS notebook to 18.04 LTS.
I read this page : https://www.liquidweb.com/kb/how-to-upgrade-ubuntu-16-04-to-ubuntu-18-04/
That page says if I follow the procedure, it will upgrade to 18.04 LTS, but I'm afraid it will upgrade directly to 20.04. (I guess by the time the article was written, there was no 20.04).
How can I go from 16.04 LTS to specifically 18.04 LTS (not to 20.04 LTS)? Is there any choice provided during the upgrade?
ADD :
After reading comments and other documents, I processed 'sudo do-release-upgrade' command.(before that I added sudo apt dist-upgrade to let it upgrade more packages considering dependencies) It took a while, and saw many update-initramfs was executed several times for several kernel versions. so I was afraid. Now it stopped with this last log and asks me if I can proceed with removing obsolte packages. (I don't know what was going on before..) I hope it's just fine to remove obsolete files.
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-141-generic
Found initrd image: /boot/initrd.img-4.15.0-141-generic
Found linux image: /boot/vmlinuz-4.15.0-140-generic
Found initrd image: /boot/initrd.img-4.15.0-140-generic
Found linux image: /boot/vmlinuz-4.15.0-118-generic
Found initrd image: /boot/initrd.img-4.15.0-118-generic
Found linux image: /boot/vmlinuz-4.15.0-117-generic
Found initrd image: /boot/initrd.img-4.15.0-117-generic
Found linux image: /boot/vmlinuz-4.15.0-112-generic
Found initrd image: /boot/initrd.img-4.15.0-112-generic
Found linux image: /boot/vmlinuz-4.15.0-107-generic
Found initrd image: /boot/initrd.img-4.15.0-107-generic
Found linux image: /boot/vmlinuz-4.15.0-106-generic
Found initrd image: /boot/initrd.img-4.15.0-106-generic
Found linux image: /boot/vmlinuz-4.15.0-101-generic
Found initrd image: /boot/initrd.img-4.15.0-101-generic
Found linux image: /boot/vmlinuz-4.13.0-37-generic
Found initrd image: /boot/initrd.img-4.13.0-37-generic
Found linux image: /boot/vmlinuz-4.13.0-36-generic
Found initrd image: /boot/initrd.img-4.13.0-36-generic
Adding boot menu entry for EFI firmware configuration
done
Processing triggers for linux-image-4.15.0-140-generic (4.15.0-140.144) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-4.15.0-140-generic
/sbin/ldconfig.real: Warning: ignoring configuration file that cannot be opened: /etc/ld.so.conf.d/x86_64-linux-gnu_EGL.conf: No such file or directory
/etc/kernel/postinst.d/zz-update-grub:
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-141-generic
Found initrd image: /boot/initrd.img-4.15.0-141-generic
Found linux image: /boot/vmlinuz-4.15.0-140-generic
Found initrd image: /boot/initrd.img-4.15.0-140-generic
Found linux image: /boot/vmlinuz-4.15.0-118-generic
Found initrd image: /boot/initrd.img-4.15.0-118-generic
Found linux image: /boot/vmlinuz-4.15.0-117-generic
Found initrd image: /boot/initrd.img-4.15.0-117-generic
Found linux image: /boot/vmlinuz-4.15.0-112-generic
Found initrd image: /boot/initrd.img-4.15.0-112-generic
Found linux image: /boot/vmlinuz-4.15.0-107-generic
Found initrd image: /boot/initrd.img-4.15.0-107-generic
Found linux image: /boot/vmlinuz-4.15.0-106-generic
Found initrd image: /boot/initrd.img-4.15.0-106-generic
Found linux image: /boot/vmlinuz-4.15.0-101-generic
Found initrd image: /boot/initrd.img-4.15.0-101-generic
Found linux image: /boot/vmlinuz-4.13.0-37-generic
Found initrd image: /boot/initrd.img-4.13.0-37-generic
Found linux image: /boot/vmlinuz-4.13.0-36-generic
Found initrd image: /boot/initrd.img-4.13.0-36-generic
Adding boot menu entry for EFI firmware configuration
done
Processing triggers for resolvconf (1.79ubuntu10.18.04.3) ...
Processing triggers for bamfdaemon (0.5.3+18.04.20180207.2-0ubuntu1) ...
Rebuilding /usr/share/applications/bamf-2.index...
Reading package lists... Done
Building dependency tree
Reading state information... Done
Checking for installed snaps
No snaps are installed yet. Try 'snap install hello-world'.
Installing snap gnome-3-26-1604
Installing snap gtk-common-themes
Installing snap gnome-calculator
Installing snap gnome-characters
Installing snap gnome-logs
Installing snap gnome-system-monitor
Searching for obsolete software
Reading state information... Done
Remove obsolete packages?
212 Packages are going to be removed.
Removing the packages can take several hours.
Continue [yN] Details [d]
I pressed y here to remove the packages. and saw update-initramfs messages and updating grub several times, and it asked me if it can restart the machine so I pressed 'y' and it rebooted. Now it's 18.04LTS! Hew.. Thanks guys.
