For an irreducible discrete series \(\pi\) of the linear group \(G\), a conjecture was made by K. Hiraga et al. [J. Am. Math. Soc. 21, No. 1, 283–304 (2008; Zbl 1131.22014)] and K. Hiraga et al. [J. Am. Math. Soc. 21, No. 4, 1211–1213 (2008; Zbl 1202.22020)]. Many authors have worked on this conjecture [D. Ciubotaru et al., Invent. Math. 187, No. 3, 589–635 (2012; Zbl 1270.20002); D. Ciubotaru and E. Opdam, Proc. Lond. Math. Soc. (3) 110, No. 3, 615–646 (2015; Zbl 1311.22022); Y. Feng and E. Opdam, Adv. Math. 375, Article ID 107406, 62 p. (2020; Zbl 1498.22015); Y. Feng et al., “Supercuspidal unipotent representations: L-packets and formal degrees”, Preprint, arXiv:1805.01888; Y. Qiu, Int. Math. Res. Not. 2012, No. 2, 239–298 (2012; Zbl 1238.22010)]. The authors of the paper under review verify the Hiraga-Ichino-Ikeda formula (conjecture) for their formal degrees for an irreducible genuine Iwahori-spherical discrete series representations of central covers.