Because Denmark opted out of the Brussels I Regulation (1215/2012), which sets out the EU rules on the jurisdiction of courts and recognition of judgments, whenever amendments are made to that Regulation, Denmark must notify the Commission of its decision whether or not it will implement the content of those amendments.  On 13 August 2014, the OJ reported (here) that Denmark had, by letter of 2 June 2014, notified the Commission of its decision to implement the contents of Regulation 542/2014.  Regulation 542/2014 amended the Brussels I Regulation to take into account the UPC (the amendments applying from 10 January 2015).  Denmark having decided to ratify the UPC Agreement, following a national referendum vote on 25 May 2014 in favour, it was necessary for Denmark to implement the UPC amendments to the Brussels I Regulation.  (Denmark deposited its instrument of ratification of the UPC Agreement on 20 June 2014.)