Verified 1.1ubuntu1.18.04.7~16.04.2 on Xenial.

$ dpkg -l unattended-upgrades | cat
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  unattended-upgrades 1.1ubuntu1.18.04.7~16.04.2 all          automatic installation of security upgrades
$ sudo unattended-upgrade --dry-run --debug --verbose
Initial blacklisted packages: 
Initial whitelisted packages: 
Starting unattended upgrades script
Allowed origins are: o=Ubuntu,a=xenial, o=Ubuntu,a=xenial-security, o=UbuntuESM,a=xenial
...
wireshark-common
wireshark-gtk
wireshark-qt
System is on metered connection, stopping
$ nmcli -t -f GENERAL.DEVICE,GENERAL.METERED dev show `ip route list 0/0 | sed -r 's/.*dev (\S*).*/\1/g'`
GENERAL.DEVICE:ens3
GENERAL.METERED:yes
$ sudo nmcli connection modify 'Wired connection 1' connection.metered no
$  nmcli -t -f GENERAL.DEVICE,GENERAL.METERED dev show `ip route list 0/0 | sed -r 's/.*dev (\S*).*/\1/g'`
GENERAL.DEVICE:ens3
GENERAL.METERED:no
$ sudo unattended-upgrade --dry-run --debug --verbose

$ sudo unattended-upgrade --dry-run --debug --verbose
Initial blacklisted packages: 
Initial whitelisted packages: 
Starting unattended upgrades script
Allowed origins are: o=Ubuntu,a=xenial, o=Ubuntu,a=xenial-security, o=UbuntuESM,a=xenial
Using (^linux-image-[0-9]+\.[0-9\.]+-.*|^linux-headers-[0-9]+\.[0-9\.]+-.*|^linux-image-extra-[0-9]+\.[0-9\.]+-.*|^linux-modules-[0-9]+\.[0-9\.]+-.*|^linux-modules-extra-[0-9]+\.[0-9\.]+-.*|^linux-signed-image-[0-9]+\.[0-9\.]+-.*|^kfreebsd-image-[0-9]+\.[0-9\.]+-.*|^kfreebsd-headers-[0-9]+\.[0-9\.]+-.*|^gnumach-image-[0-9]+\.[0-9\.]+-.*|^.*-modules-[0-9]+\.[0-9\.]+-.*|^.*-kernel-[0-9]+\.[0-9\.]+-.*|^linux-backports-modules-.*-[0-9]+\.[0-9\.]+-.*|^linux-modules-.*-[0-9]+\.[0-9\.]+-.*|^linux-tools-[0-9]+\.[0-9\.]+-.*|^linux-cloud-tools-[0-9]+\.[0-9\.]+-.*) regexp to find kernel packages
Using (^linux-image-4\.15\.0\-39\-generic$|^linux-headers-4\.15\.0\-39\-generic$|^linux-image-extra-4\.15\.0\-39\-generic$|^linux-modules-4\.15\.0\-39\-generic$|^linux-modules-extra-4\.15\.0\-39\-generic$|^linux-signed-image-4\.15\.0\-39\-generic$|^kfreebsd-image-4\.15\.0\-39\-generic$|^kfreebsd-headers-4\.15\.0\-39\-generic$|^gnumach-image-4\.15\.0\-39\-generic$|^.*-modules-4\.15\.0\-39\-generic$|^.*-kernel-4\.15\.0\-39\-generic$|^linux-backports-modules-.*-4\.15\.0\-39\-generic$|^linux-modules-.*-4\.15\.0\-39\-generic$|^linux-tools-4\.15\.0\-39\-generic$|^linux-cloud-tools-4\.15\.0\-39\-generic$) regexp to find running kernel packages
Checking: apt ([<Origin component:'main' archive:'xenial-updates' origin:'Ubuntu' label:'Ubuntu' site:'be.archive.ubuntu.com' isTrusted:True>])
adjusting candidate version: apt=1.2.29ubuntu0.1
...
No conffiles in deb /var/cache/apt/archives/wireshark_2.6.6-1~ubuntu16.04.0_amd64.deb (There is no member named 'conffiles')
blacklist: []
whitelist: []
Configured to install on shutdown, so exiting now
$
$ sudo nmcli connection modify 'Wired connection 1' connection.metered yes
ubuntu@ubuntu-Standard-PC-i440FX-PIIX-1996:~$  nmcli -t -f GENERAL.DEVICE,GENERAL.METERED dev show `ip route list 0/0 | sed -r 's/.*dev (\S*).*/\1/g'`
GENERAL.DEVICE:ens3
GENERAL.METERED:yes
$ echo ' Unattended-Upgrade::Skip-Updates-On-Metered-Connections "false";' | sudo tee /etc/apt/apt.conf.d/51unattended-upgrades-metered
 Unattended-Upgrade::Skip-Updates-On-Metered-Connections "false";
$ sudo eatmydata unattended-upgrade --dry-run --debug --verbose
Initial blacklisted packages: 
Initial whitelisted packages: 
Starting unattended upgrades script
Allowed origins are: o=Ubuntu,a=xenial, o=Ubuntu,a=xenial-security, o=UbuntuESM,a=xenial
...
check_conffile_prompt(/var/cache/apt/archives/wireshark_2.6.6-1~ubuntu16.04.0_amd64.deb)
found pkg: wireshark
No conffiles in deb /var/cache/apt/archives/wireshark_2.6.6-1~ubuntu16.04.0_amd64.deb (There is no member named 'conffiles')
blacklist: []
whitelist: []
Configured to install on shutdown, so exiting now