This is actually a firming and increase of the order, plus a conversion to all-CS300.
The initial LOI was for 3 CS100, 7 CS300 + 20 options. It seems they have exercised their options +2 more, and added 10 options on top.
Great news for BBD, firm orders now stand at 180. I expect more airlines to sign up over the year, once first flight happens.
And on a side note, with first flight only months away we still don't know who the mysterious first customer is...