The upgrade needs a total of 27.4 M free space on disk '/boot'. Please free at least an additional 9,027 k of disk space on '/boot'. Empty your trash and remove temporary packages of former installations using 'sudo apt-get clean'.
How to get free space for installing new updates? I checked the boot in the file system. There were different versions of the same thing. Can I just delete older versions by myself to get free space?