The DfT has today published the May 2022 Abellio East Midlands Franchise agreement (as updated)
It is 800+ pages long, but about page 200 in tables are various proposed rolling stock, and here is a summary (includes changes since 2020)
class 156, 18 vehicles (note 8) replacing class 153
class 180, 20 vehicles, replacing 2+6 HST
class 170/2, 46 vehicles (note 9) replacing 156s and half 158s
class 170/3, 15 vehicles (note 10) replacing class 153
class 170/3, 12 vehicles (note 11), remove remaining 15x
class 171/2, 20 vehicles (note 12), remove remaining 15x
class 171/3, 6 vehicles (note 13), remove remaining 15x
also 23 HST power car, 78 trailers,(note 14)
and the 84 class 360s and 165 bi-modes