Hello - I just returned back to the USA from India, where I spent nearly 3 weeks. Here is a summary of the airports that I visited in India:

BOM (International)
BOM (Domestic)
CJB (Domestic)
KOC (Domestic)
BLR (Domestic)
GOI (Domestic)
DEL (Domestic)
DEL (International)

At none of these airports was the Aarogya setu app asked for. So I agree with the poster above, it looks like the government is not making this mandatory at any of the airports any longer, and just a suggestion.