HAProxy stands for High Availability Proxy, If you are running the Ubuntu Yakkety-16.10 LTS operating system and install  HAProxy-1.7-stable version

First, need to enable a Dedicated PPA using below commands on Ubuntu Yakkety-16.10 LTS

# apt-get install software-properties-common

# add-apt-repository ppa:vbernat/haproxy-1.7

execute the below commands to install HAProxy-1.7-stable

# apt-get update

# apt-get install haproxy -t trusty-backports

You will get HAProxy 1.7-stable version, which means you may not a latest one.