That's a good question.  Actually, it's an excellent question!  But nobody has the answer.

It's too bad that Intuit got rid of their form update phone line.  You used to be able to call 867-5309 and get up to date information about those kinds of things.  Jenny was the most helpful employee working that phone line.

I have this bookmarked and check on it regularly

https://www.irs.gov/affordable-care-act/individuals-and-families/the-premium-tax-credit-the-basics

and this for other items

https://www.irs.gov/forms-pubs/changes-to-current-forms-publications

That way I'll know when a change happens.