[2] In 2016, Dolfijn was taken out of service after being active for years by the Royal Netherlands Navy to perform maintenance and modernize its systems.

[4] Besides changing the software suit, hardware components were also either replaced or upgraded with newer versions.

[11] The submarine changed course near Scotland to return to the Netherlands two weeks early, arriving in Den Helder on 3 April.

[11][12] Dolfijn made a routine port visit to the United States at Naval Station Mayport, Florida in May 2022.

[14] During this mission Dolfijn kept an eye on naval ships and submarines that do not belong to NATO countries.