Well there you go. Decision should be made by mid-year according to this article:

https://www.bloomberg.com/news/articles/2019-01-22/spirit-airlines-sees-decision-by-mid-year-on-adding-smaller-jets?fbclid=IwAR2MTIBxJWBKsHvIRBxiK9Ndy-J1ACgNXBDOajE8xw8zbtN1NxeUx3ERKMc

This should give Boeing enough time to come up with a fleet-swap scenario for cheap... . No doubt the folks at Embraer are desperate to sell more E2 airframes.