Looking in the "The Last Ship" by Sting as a mirror, wikipedia says this:
In September 2011, it was confirmed that British musician Sting was working on a musical,[2] following rumours the previous year.[3] A first reading took place in Manhattan in October that year,[4] with a further reading in Newcastle in February 2012[5] and ultimately a full staged reading[6] for the musical was held in 2013.[7] In September 2013, the show was officially confirmed and it was announced that the show would premiere in Chicago in 10 June 2014.
So it was rumoured in 2010, confirmed in 2011, readed in 2012, rehearsed in a stage in 2013 and premiered in 2014
MK´s one it´s been rumoured between 2016/2017, following Sting´s example... confirmed 2018, readed 2019, rehearsed in 2020 and premiered in 2021?
That´s a lot of time for a project, it is, but... that´s how Sting musical developed...