The IKZ is the first and foremost place where one can be regularly and directly informed about the development of Old Catholic theology and about the results of historical research in Old Catholicism. The IKZ reports on the ecumenical concerns of the Old Catholic Church, whose primary partners traditionally include Eastern Orthodoxy and the Anglican Communion of Churches.

In the Ecclesiastical Chronicle, on the one hand, the official announcements of the “International Old Catholic Bishops’ Conference” (IBK) – the first organ of the Utrecht Union – are published, as well as any and all important decisions from the Old Catholic local or national churches. On the other hand, events of significance to Old Catholicism from worldwide ecumenism are taken up and communicated.