Had a look into this and someone else has expressed the same worries.
Someone called “Surgeworks” wrote:
There is no mention of the license for many of the materials used on this app. The Daily Readings and the New American Bible are being used in conflict of the USCCB (United States Conference of Catholic Bishops) and CCD (Confraternity of Christian Doctrine) copyright. All copyrighted material should include appropriate acknowledgments and notice of the copyright owner and it is glaringly obvious in its absence indicating much of this content is in violation of copyright. I can appreciate that this app is being offered for free and the developer took time to create it, but that does not make it right to violate copyright or to use translations not approved for liturgical celebration of the Liturgy of the Hours. Many Catholic developers are legal and pay appropriate fees and royalties that support organizations such as the USCCB. and such organizations use the funds to further their mission and support good causes such as The Confraternity of Christian Doctrine (CCD) owns the copyright on the New American Bible, revised edition translation. The copyright allows the owner to protect the integrity of the text so that individuals may not introduce changes without permission. Royalty fees earned by licensing the text to companies who publish and sell Bibles help to provide funds for Scripture scholarship and other educational needs.”
These were basically my fears. I guess I will be using the NAB on www.vatican.va for now. But then again this app may be perfectly legal. I’m still not too sure.