dnf install --allowerasing kernel-4.2.3
DNF either installs the package, or clearly indicates why the package cannot be installed.
Last metadata expiration check performed 2:00:05 ago on Mon Feb 29 19:18:59 2016.
Error: conflicting requests
This is not an acceptable error message; it contains very little useful information.
*** This bug has been marked as a duplicate of bug 1191611 ***