Please bump to 3.0 We're trying to remove all uses of dev-qt/qtquick1 from the tree, and kadu-2.1 is one of the very last consumers of it. Fortunately kadu-3.0 dropped that dependency in favor of QtQml/QtQuick2 (dev-qt/qtdeclarative:5 in gentoo). Thanks!
I could bump it now but only with masked jabber support since 3.0 brings dependency to qxmpp in Qt5 variant that we don't have in tree yet.
As for your QtQuick1 dependency, I removed it with kadu-2.1-r1.