The volume to which an article belongs is determined by the date of acceptance, rather than the date of publication (e.g. the article accepted 18 December 2019 and published 22 January 2020 belongs to volume 1, rather than volume 2)
Articles within each volume have consecutive numbering up to volume 2, article 10 (24 September 2020), after which individual articles are given six digit numbers corresponding to the article's doi (e.g. volume 2, article 547758 (29 September 2020))