3. For data processing services other than those referred to in paragraph 1 of this Article, providers of data processing services shall ensure compatibility with common specifications based on open interoperability specifications or harmonised standards for interoperability at least 12 months after the references to those common specifications or harmonised standards for interoperability of data processing services were published in the central Union standards repository for the interoperability of data processing services following the publication of the underlying implementing acts in the Official Journal of the European Union in accordance with Article 35(8).