cannot upgrade kernel, not a space problem

[oxy]

hi

> As I understand it, 3.13.0-54 is the latest kernel and your problems
> with 3.13.0-48 were problems with an old kernel package. Or do you
> really want to use that older kernel?

the latest kernel is
linux-image-extra-3.16.0-39-generic
or
linux-image-extra-3.19.0-20-generic

according to http://packages.ubuntu.com/trusty/kernel

So why i cannot upgrade?