Verified 1.1ubuntu1.18.04.7~16.04.2 on Xenial:

ubuntu@ip-172-31-9-2:~$ 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


ubuntu@ip-172-31-9-2:~$ sudo service apt-daily-upgrade start &  tail -f /var/log/unattended-upgrades/unattended-upgrades.log
[2] 13368
2019-04-09 16:11:45,975 INFO Initial blacklisted packages: 
2019-04-09 16:11:45,975 INFO Initial whitelisted packages: 
2019-04-09 16:11:45,976 INFO Starting unattended upgrades script
2019-04-09 16:11:45,976 INFO Allowed origins are: o=Ubuntu,a=xenial, o=Ubuntu,a=xenial-security, o=UbuntuESM,a=xenial, o=Ubuntu,a=xenial-updates
2019-04-09 16:13:06,974 INFO Initial blacklisted packages: 
2019-04-09 16:13:06,974 INFO Initial whitelisted packages: 
2019-04-09 16:13:06,974 INFO Starting unattended upgrades script
2019-04-09 16:13:06,974 INFO Allowed origins are: o=Ubuntu,a=xenial, o=Ubuntu,a=xenial-security, o=UbuntuESM,a=xenial, o=Ubuntu,a=xenial-updates
2019-04-09 16:13:11,782 INFO Packages that will be upgraded: apt apt-transport-https apt-utils busybox-initramfs busybox-static cloud-init distro-info-data file grub-common grub-legacy-ec2 grub-pc grub-pc-bin grub2-common libapt-inst2.0 libapt-pkg5.0 libmagic1 libpam-systemd libpolkit-agent-1-0 libpolkit-backend-1-0 libpolkit-gobject-1-0 libsystemd0 libudev1 linux-aws linux-headers-aws linux-image-aws ntfs-3g policykit-1 rsyslog snapd systemd systemd-sysv ubuntu-core-launcher udev wget
2019-04-09 16:13:11,782 INFO Writing dpkg log to /var/log/unattended-upgrades/unattended-upgrades-dpkg.log
2019-04-09 16:13:17,835 WARNING SIGTERM received, will stop
2019-04-09 16:13:18,514 WARNING SIGNAL received, stopping

... connection lost.

After resume:
$ sudo apt upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following NEW packages will be installed:
  linux-aws-headers-4.4.0-1079 linux-headers-4.4.0-1079-aws linux-image-4.4.0-1079-aws linux-modules-4.4.0-1079-aws
The following packages will be upgraded:
  apt apt-transport-https apt-utils busybox-initramfs busybox-static cloud-init file grub-common grub-legacy-ec2 grub-pc grub-pc-bin grub2-common libapt-inst2.0
  libapt-pkg5.0 liblxc1 libmagic1 libpam-systemd libpolkit-agent-1-0 libpolkit-backend-1-0 libpolkit-gobject-1-0 libsystemd0 libudev1 linux-aws linux-headers-aws
  linux-image-aws login lxc-common ntfs-3g passwd policykit-1 python-apt-common python3-apt rsyslog snapd systemd systemd-sysv ubuntu-core-launcher udev uidmap wget
40 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
Need to get 15.9 MB/56.1 MB of archives.
After this operation, 118 MB of additional disk space will be used.
Do you want to continue? [Y/n] n
Abort.
ubuntu@ip-172-31-9-2:~$ journalctl -a
Apr 09 16:13:17 ip-172-31-9-2 systemd[1]: Reached target Sleep.
Apr 09 16:13:17 ip-172-31-9-2 systemd[1]: Starting Hibernate...
Apr 09 16:13:17 ip-172-31-9-2 kernel: PM: Hibernation mode set to 'platform'
Apr 09 16:13:19 ip-172-31-9-2 sudo[13368]: pam_unix(sudo:session): session closed for user root
Apr 09 16:13:19 ip-172-31-9-2 systemd[1]: Started Daily apt upgrade and clean activities.
Apr 09 16:13:19 ip-172-31-9-2 systemd-sleep[13502]: Suspending system...
Apr 09 16:15:58 ip-172-31-9-2 kernel: PM: Syncing filesystems ... done.
Apr 09 16:15:58 ip-172-31-9-2 kernel: Freezing user space processes ... (elapsed 0.001 seconds) done.
Apr 09 16:15:58 ip-172-31-9-2 kernel: PM: Marking nosave pages: [mem 0x00000000-0x00000fff]
Apr 09 16:15:58 ip-172-31-9-2 kernel: PM: Marking nosave pages: [mem 0x0009e000-0x000fffff]
Apr 09 16:15:58 ip-172-31-9-2 kernel: PM: Basic memory bitmaps created
...