I check, and there is an achived thread about this, but that was about the LOI for the Boeing order.
MI has firmed up their order with Boeing for 23 B-737-800s and 31 B-737-8MAXs. These B-737s will fly along side of WI's current fleet of 6 A-319s and 16 A-320s (which were new orders from 2006). Airbus has 2 more A-320s to be delivered and SilkAir holds 4 options.
SilkAir also now has 14 options for the B-737-8MAX.