Comment 9 for bug 2015241

Xenial

$ cat /etc/os-release; uname -a; dpkg -l ubuntu-advantage-tools; sudo pro attach <key>
NAME="Ubuntu"
VERSION="16.04.7 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.7 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial
Linux zygarde 4.4.0-210-generic #242-Ubuntu SMP Fri Apr 16 10:00:19 UTC 2021 aarch64 aarch64 aarch64 GNU/Linux
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=========================================-=========================-=========================-========================================================================================
ii ubuntu-advantage-tools 27.13.6~16.04.1 arm64 management tools for Ubuntu Pro
This machine is now attached to 'Ubuntu Pro (Apps-only)'

SERVICE ENTITLED STATUS DESCRIPTION
ros yes disabled Security Updates for the Robot Operating System
ros-updates yes disabled All Updates for the Robot Operating System

NOTICES
Operation in progress: pro attach

Enable services with: pro enable <service>

                Account: Canonical - staff
           Subscription: Ubuntu Pro (Apps-only)
            Valid until: Fri Dec 31 23:59:59 3999 UTC
Technical support level: essential

$ sudo pro enable livepatch
One moment, checking your subscription first
Livepatch is not available for platform arm64.
Supported platforms are: amd64.

$ sudo pro detach; source /etc/os-release

$ echo "deb http://ports.ubuntu.com/ubuntu-ports ${UBUNTU_CODENAME}-proposed universe multiverse main restricted" | sudo tee -a /etc/apt/sources.list; sudo apt update; sudo apt dist-upgrade -y

Hit:1 http://ports.ubuntu.com/ubuntu-ports xenial InRelease
Hit:2 http://ports.ubuntu.com/ubuntu-ports xenial-updates InRelease
Hit:3 http://ports.ubuntu.com/ubuntu-ports xenial-security InRelease
Hit:4 http://ports.ubuntu.com/ubuntu-ports xenial-backports InRelease
Get:5 http://ports.ubuntu.com/ubuntu-ports xenial-proposed InRelease [251 kB]
Get:6 http://ports.ubuntu.com/ubuntu-ports xenial-proposed/universe arm64 Packages [4960 B]
Get:7 http://ports.ubuntu.com/ubuntu-ports xenial-proposed/universe Translation-en [3204 B]
Get:8 http://ports.ubuntu.com/ubuntu-ports xenial-proposed/main arm64 Packages [14.6 kB]
Get:9 http://ports.ubuntu.com/ubuntu-ports xenial-proposed/main Translation-en [7880 B]
Fetched 282 kB in 1s (180 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
1 package can be upgraded. Run 'apt list --upgradable' to see it.
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  ubuntu-advantage-tools
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 171 kB of archives.
After this operation, 13.3 kB of additional disk space will be used.
Get:1 http://ports.ubuntu.com/ubuntu-ports xenial-proposed/main arm64 ubuntu-advantage-tools arm64 27.14.4~16.04 [171 kB]
Fetched 171 kB in 0s (356 kB/s)
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
 LANGUAGE = (unset),
 LC_ALL = (unset),
 LC_TIME = "de_DE.UTF-8",
 LC_MONETARY = "de_DE.UTF-8",
 LC_ADDRESS = "de_DE.UTF-8",
 LC_TELEPHONE = "de_DE.UTF-8",
 LC_NAME = "de_DE.UTF-8",
 LC_MEASUREMENT = "de_DE.UTF-8",
 LC_IDENTIFICATION = "de_DE.UTF-8",
 LC_NUMERIC = "de_DE.UTF-8",
 LC_PAPER = "de_DE.UTF-8",
 LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").
locale: Cannot set LC_ALL to default locale: No such file or directory
Preconfiguring packages ...
(Reading database ... 59584 files and directories currently installed.)
Preparing to unpack .../ubuntu-advantage-tools_27.14.4~16.04_arm64.deb ...
Unpacking ubuntu-advantage-tools (27.14.4~16.04) over (27.13.6~16.04.1) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up ubuntu-advantage-tools (27.14.4~16.04) ...
Installing new version of config file /etc/apt/apt.conf.d/20apt-esm-hook.conf ...
Installing new version of config file /etc/ubuntu-advantage/uaclient.conf ...
Installing new version of config file /etc/update-motd.d/91-contract-ua-esm-status ...
locale: Cannot set LC_ALL to default locale: No such file or directory
Removing obsolete conffile /etc/update-motd.d/88-esm-announce ...

$ dpkg -l ubuntu-advantage-tools; sudo pro attach <key>
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=========================================-=========================-=========================-========================================================================================
ii ubuntu-advantage-tools 27.14.4~16.04 arm64 management tools for Ubuntu Pro

This machine is now attached to 'Ubuntu Pro (Apps-only)'

SERVICE ENTITLED STATUS DESCRIPTION
ros yes disabled Security Updates for the Robot Operating System
ros-updates yes disabled All Updates for the Robot Operating System

NOTICES
Operation in progress: pro attach

Enable services with: pro enable <service>

                Account: Canonical - staff
           Subscription: Ubuntu Pro (Apps-only)
            Valid until: Fri Dec 31 23:59:59 3999 UTC
Technical support level: essential

$ sudo pro enable livepatch
One moment, checking your subscription first
Livepatch is not available for platform arm64.
Supported platforms are: amd64.

Working without issues on Xenial now (proper detection of livepatch not being available)