Verified 1.1.12+dfsg1-0ubuntu1~16.04.0 on Xenial:

ubuntu@ip-172-31-23-71:~$ sudo apt install ec2-instance-connect 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  ec2-instance-connect
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 11.4 kB of archives.
After this operation, 48.1 kB of additional disk space will be used.
Get:1 http://us-east-2.ec2.archive.ubuntu.com/ubuntu xenial-updates/universe amd64 ec2-instance-connect all 1.1.9-0ubuntu3~16.04.1 [11.4 kB]
Fetched 11.4 kB in 0s (106 kB/s)          
Selecting previously unselected package ec2-instance-connect.
(Reading database ... 76553 files and directories currently installed.)
Preparing to unpack .../ec2-instance-connect_1.1.9-0ubuntu3~16.04.1_all.deb ...
Created system user ec2-instance-connect
Unpacking ec2-instance-connect (1.1.9-0ubuntu3~16.04.1) ...
Setting up ec2-instance-connect (1.1.9-0ubuntu3~16.04.1) ...
sshd override added, restarting daemon
ubuntu@ip-172-31-23-71:~$ sudo sed -i s/backports/proposed/ /etc/apt/sources.list
ubuntu@ip-172-31-23-71:~$ sudo apt update -qq
24 packages can be upgraded. Run 'apt list --upgradable' to see them.
ubuntu@ip-172-31-23-71:~$ sudo apt install -q ec2-instance-connect 
Reading package lists...
Building dependency tree...
Reading state information...
The following packages will be upgraded:
  ec2-instance-connect
1 upgraded, 0 newly installed, 0 to remove and 23 not upgraded.
Need to get 12.7 kB of archives.
After this operation, 7,168 B of additional disk space will be used.
Get:1 http://us-east-2.ec2.archive.ubuntu.com/ubuntu xenial-proposed/universe amd64 ec2-instance-connect all 1.1.12+dfsg1-0ubuntu1~16.04.0 [12.7 kB]
Fetched 12.7 kB in 0s (247 kB/s)
(Reading database ... 76562 files and directories currently installed.)
Preparing to unpack .../ec2-instance-connect_1.1.12+dfsg1-0ubuntu1~16.04.0_all.deb ...
Unpacking ec2-instance-connect (1.1.12+dfsg1-0ubuntu1~16.04.0) over (1.1.9-0ubuntu3~16.04.1) ...
Setting up ec2-instance-connect (1.1.12+dfsg1-0ubuntu1~16.04.0) ...
ubuntu@ip-172-31-23-71:~$ sudo apt purge ec2-instance-connect
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  ec2-instance-connect*
0 upgraded, 0 newly installed, 1 to remove and 23 not upgraded.
After this operation, 55.3 kB disk space will be freed.
Do you want to continue? [Y/n] 
(Reading database ... 76562 files and directories currently installed.)
Removing ec2-instance-connect (1.1.12+dfsg1-0ubuntu1~16.04.0) ...
sshd override removed, restarting daemon...
Deleted system user ec2-instance-connect
Purging configuration files for ec2-instance-connect (1.1.12+dfsg1-0ubuntu1~16.04.0) ...
Deleted system user ec2-instance-connect
(failed reverse-i-search)`apit in': sudo ^Ct purge ec2-instance-connect
ubuntu@ip-172-31-23-71:~$ sudo apt install -q ec2-instance-connect 
Reading package lists...
Building dependency tree...
Reading state information...
The following NEW packages will be installed:
  ec2-instance-connect
0 upgraded, 1 newly installed, 0 to remove and 23 not upgraded.
Need to get 12.7 kB of archives.
After this operation, 55.3 kB of additional disk space will be used.
Get:1 http://us-east-2.ec2.archive.ubuntu.com/ubuntu xenial-proposed/universe amd64 ec2-instance-connect all 1.1.12+dfsg1-0ubuntu1~16.04.0 [12.7 kB]
Fetched 12.7 kB in 0s (0 B/s)
Selecting previously unselected package ec2-instance-connect.
(Reading database ... 76553 files and directories currently installed.)
Preparing to unpack .../ec2-instance-connect_1.1.12+dfsg1-0ubuntu1~16.04.0_all.deb ...
Created system user ec2-instance-connect
Unpacking ec2-instance-connect (1.1.12+dfsg1-0ubuntu1~16.04.0) ...
Setting up ec2-instance-connect (1.1.12+dfsg1-0ubuntu1~16.04.0) ...
sshd override added, restarting daemon
ubuntu@ip-172-31-23-71:~$ 


I used the following aws cli command to switch to IMDSv2:

root@aws-cli-br-cc:~# aws ec2 modify-instance-metadata-options --instance-id i-021a1d1da29c13d4a --http-tokens required --http-endpoint enabled
{
    "InstanceId": "i-021a1d1da29c13d4a",
    "InstanceMetadataOptions": {
        "State": "pending",
        "HttpTokens": "required",
        "HttpPutResponseHopLimit": 1,
        "HttpEndpoint": "enabled"
    }
}