apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.4.0-81 linux-headers-4.4.0-81-generic linux-headers-4.4.0-83
  linux-headers-4.4.0-83-generic linux-headers-4.4.0-87
  linux-headers-4.4.0-87-generic linux-image-4.4.0-81-generic
  linux-image-4.4.0-83-generic linux-image-4.4.0-87-generic
  linux-image-extra-4.4.0-81-generic linux-image-extra-4.4.0-83-generic
  linux-image-extra-4.4.0-87-generic
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.