emerge -pqv '=net-print/cndrvcups-common-2.56-r1'

emerge -pqv '=net-print/cndrvcups-common-2.56-r1'
[ebuild     U ] net-print/cndrvcups-common-2.56-r1 [2.20-r1] USE="cngplp"

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

net-print/cndrvcups-common:0

  (net-print/cndrvcups-common-2.20-r1::x-portage, installed) pulled in by
    =net-print/cndrvcups-common-2.20-r1 required by (net-print/cndrvcups-capt-2.20-r1::x-portage, installed)

  (net-print/cndrvcups-common-2.56-r1::x-portage, ebuild scheduled for merge) pulled in by
    =net-print/cndrvcups-common-2.56-r1