The Court of Justice delivered on 9 September 2021 its judgment in case C‑422/20 (RK v CR), which is about the Succession Regulation:

“1. Article 7(a) of Regulation (EU) No 650/2012 […] must be interpreted as meaning that, in order for there to have been a declining of jurisdiction, within the meaning of Article 6(a) of that regulation, in favour of the courts of the Member State whose law was chosen by the deceased, it is not necessary for the court previously seised to have expressly declined jurisdiction, but that intention must be unequivocally apparent from the decision that it delivered in that regard.

2. Article 6(a), Article 7(a) and Article 39 of Regulation No 650/2012 must be interpreted as meaning that the court of the Member State seised following a declining of jurisdiction is not competent to examine whether the conditions set out in those provisions were satisfied in order for the court previously seised to decline jurisdiction.

3. Article 6(a) and Article 7(a) of Regulation No 650/2012 must be interpreted as meaning that the rules of jurisdiction set out in those provisions also apply in the event that, in his or her will, drawn up before 17 August 2015, the deceased had not chosen the law applicable to the succession, and that the designation of that law can be inferred from Article 83(4) of that regulation alone”.

Source: https://curia.europa.eu/juris/document/document.jsf?text=&docid=245756&pageIndex=0&doclang=EN&mode=req&dir=&occ=first&part=1&cid=2104