when I run upgrade in my ubuntu 10.04,the result is
~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
git git-all git-arch git-cvs git-daemon-run git-email git-gui git-man git-svn gitk gitweb linux-generic linux-headers-generic linux-image-generic ubufox
0 upgraded, 0 newly installed, 0 to remove and 15 not upgraded.
why are some packages not upgraded?