While my old and battered four volumes of the Liturgica Horarum have been for repairs at The Book Doctor (who deserve their own review for their excellent restoration of old books), I have used several digital editions of the office. All of these have their strengths and limitations. Universalis is good but many choices in the office are made for you. For example, if you want to use the hymns from the Common in the sanctoral cycle on memorials and optional memorials, there is no access to the Common. The Liturgica Horarum app by Rafael Cereceda solves this problem but requires a considerable amount of navigating to get the elements of the office that you want. The best and most efficient program I have found is the Libreria Editrice Vaticana digital edition: www.breviariodigitale.com. First of all this is a complete reproduction of the printed edition, you have in your hands what you have in your hands when you read the printed editions. To this is added a sidebar which easily allows you to navigate between the Proper of Time, the Sanctoral Cycle, the Commons, and the Psalter. Also the General Instruction of the Liturgy is available to answer most questions you might have about the rubrics. Yes, there is a certain amount of turning pages to get to what you need but this is even more true with the printed edition. The text is readable and clear. Finally I must say that the price is right: 11,50 euros: currently 1 euro = $1.09. Even if you have the printed edition, this digital format is indispensable, when you are traveling or when you are praying in your parish church and do not want to lug along a book, e.g. at a Holy Hour. In my opinion, by the way, if you want to improve your liturgical Latin, it is much better not to have the vernacular next to the Latin text.