maybe next year. maybe not at all. I suspect Turbotax does not support forms that it believes will be used by only a small fraction of its users. Many who need these forms would use paid preparers.
your options
1) e-file without it and then paper file an amended return where the form is prepared manually
2) prepare manually and paper file your entire return.
https://www.irs.gov/site-index-search?search=8990&field_pup_historical_1=1&field_pup_historical=1
