http://www.legislation.gov.uk/eur/2012/1273/article/21/adoptedCouncil Regulation (EU) No 1273/2012 of 20 December 2012 on migration from the Schengen Information System (SIS 1+) to the second generation Schengen Information System (SIS II) (recast)Council Regulation (EU) No 1273/2012Council Regulation (EU) No 1273/2012 of 20 December 2012 on migration from the Schengen Information System (SIS 1+) to the second generation Schengen Information System (SIS II) (recast)2020-12-10King's Printer of Acts of Parliamenthttps://webarchive.nationalarchives.gov.uk/eu-exit/https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R1273texttext/xmlen
Article 21Entry into force and applicability

This Regulation shall enter into force on the day following that of its publication in the Official Journal of the European Union.

It shall expire upon the termination of the migration as referred to in the third subparagraph of Article 11(3). If that date cannot be complied with due to outstanding technical difficulties related to the migration process, it shall expire on a date to be fixed by the Council, acting in accordance with Article 55(2) of Regulation (EC) No 1987/2006.