Can't update ubuntu to 18.04, what's wrong?

Question

ubuntu

Good afternoon, I can't update Ubuntu, what should I do?
Ubuntu is zero, just installed. Version 16.04.4 Updated
everything (update, upgrade and dist-upgrade) and started the installation (do-release-upgrade -d).
As a result, an error, and what to do - I do not understand. Here:

sudo: update: command not found
[email protected]:~# sudo apt update
Hit:1 http://ua.archive.ubuntu.com/ubuntu xenial InRelease
Hit:2 http://ua.archive.ubuntu.com/ubuntu xenial-updates InRelease
Hit:3 http://ua.archive.ubuntu.com/ubuntu xenial-backports InRelease
Hit:4 http://security.ubuntu.com/ubuntu xenial-security InRelease
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.
[email protected]:~# sudo apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
[email protected]:~# sudo apt dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
[email protected]:~# clear
[email protected]:~# sudo do-release-upgrade
Checking for a new Ubuntu release
No new release found.
[email protected]:~# sudo do-release-upgrade -d
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [819 B]
Get:2 Upgrade tool [1,257 kB]
Fetched 1,258 kB in 0s (0 B/s)
authenticate 'bionic.tar.gz' against 'bionic.tar.gz.gpg'
extracting 'bionic.tar.gz'
Reading state information... Done

Calculating the changes

Calculating the changes

Not enough free disk space

The upgrade has aborted. The upgrade needs a total of 93.9 M free
space on disk '/boot'. Please free at least an additional 18.8 M of
disk space on '/boot'. You can remove old kernels using 'sudo apt
autoremove' and you could also set COMPRESS=xz in
/etc/initramfs-tools/initramfs.conf to reduce the size of your
initramfs.


Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
=== Command detached from window (Tue Jun 19 06:35:24 2018) ===
=== Command terminated with exit status 1 (Tue Jun 19 06:35:34 2018) ===

Thank you in advance!

Answer 1

Well, in the same place in black and white, English in Russian there is no place on the /boot partition

Answer 2

Do sudo apt autoremove
This can free up space on /boot from old kernel files

Answer 3

I tried to upgrade on two LAMP servers from 16.04 to 18.04 - in both cases I broke php, restored it from the image, remained on 16.04, and there are enough such cases.

Answer 4

sudo LANG=C do-release-upgrade
This will disable multibyte encoding, switch to default language (english)