Description of problem:
On my system, dhclient cannot be upgraded as:
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# rpm -q dhclient libdhcp
dhclient-4.1.0-12.fc11.i586
libdhcp-1.99.8-1.fc10.i386
[root@localhost System]# yum --disablerepo=koji-10 upgrade dhclient
Loaded plugins: dellsysidplugin2
Setting up Upgrade Process
Resolving Dependencies
There are unfinished transactions remaining. You might consider running yum-complete-transaction first to finish them.
--> Running transaction check
---> Package dhclient.i586 12:4.1.0-13.fc11 set to be updated
--> Processing Dependency: libdhcp4client-4.0.so.0 for package: libdhcp
--> Finished Dependency Resolution
libdhcp-1.99.8-1.fc10.i386 from installed has depsolving problems
  --> Missing Dependency: libdhcp4client-4.0.so.0 is needed by package libdhcp-1.99.8-1.fc10.i386 (installed)
Error: Missing Dependency: libdhcp4client-4.0.so.0 is needed by package libdhcp-1.99.8-1.fc10.i386 (installed)
 You could try using --skip-broken to work around the problem
 You could try running: package-cleanup --problems
                        package-cleanup --dupes
                        rpm -Va --nofiles --nodigest
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Version-Release number of selected component (if applicable):
dhclient-4.1.0-12.fc11.i586
libdhcp-1.99.8-1.fc10.i386


How reproducible:
100%

Steps to Reproduce:
1. See above
2.
3.

Additional info:
For F-10 -> F-11 upgrade path, some package must obsolete
libdhcp{-devel}.