install php gd library at latest version

sudo apt-get install php5-gd

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package php5-gd is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'php5-gd' has no installation candidate

sudo apt-get install php7.0-gd

sudo apt-get install phpx.y-gd