Install this version:
emerge -a =kde-apps/kontactinterface-26.03.90
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =kde-apps/kontactinterface-26.03.90
Or alternatively:
emerge --autounmask-write -a =kde-apps/kontactinterface-26.03.90
# Copyright 1999-2026 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
ECM_QTHELP="false" # TODO: Port to ECMGenerateQDoc
KFMIN=6.22.0
QTMIN=6.10.1
inherit ecm gear.kde.org
DESCRIPTION="Library for embedding KParts in a Kontact component"
HOMEPAGE="https://api.kde.org/kdepim/kontactinterface/html/index.html"
LICENSE="GPL-2+ LGPL-2.1+"
SLOT="6/$(ver_cut 1-2)"
KEYWORDS="~amd64 ~arm64"
IUSE=""
# slot op: Uses Qt::GuiPrivate for qtx11extras_p.h
DEPEND="
>=dev-qt/qtbase-${QTMIN}:6=[dbus,gui,widgets,X,xml]
>=kde-frameworks/kcoreaddons-${KFMIN}:6
>=kde-frameworks/kio-${KFMIN}:6
>=kde-frameworks/kparts-${KFMIN}:6
>=kde-frameworks/kwindowsystem-${KFMIN}:6[X]
>=kde-frameworks/kxmlgui-${KFMIN}:6
"
RDEPEND="${DEPEND}"
>=dev-qt/qtbase-6.10.1:6=[dbus,gui,widgets,X,xml] >=kde-frameworks/kcoreaddons-6.22.0:6 >=kde-frameworks/kio-:6 >=kde-frameworks/kparts-:6 >=kde-frameworks/kwindowsystem-:6[X] >=kde-frameworks/kxmlgui-:6
>=dev-qt/qtbase-6.10.1:6=[dbus,gui,widgets,X,xml] >=kde-frameworks/kcoreaddons-6.22.0:6 >=kde-frameworks/kio-:6 >=kde-frameworks/kparts-:6 >=kde-frameworks/kwindowsystem-:6[X] >=kde-frameworks/kxmlgui-:6