B2B, B2G (supplies to government/notified entities), exports, deemed exports and SEZ supplies, plus credit and debit notes — for registered persons whose AATO exceeded ₹5 crore in ANY financial year from FY2017-18 onwards. B2C is out of scope for IRN (dynamic-QR rules apply separately to B2C for AATO > ₹500 crore). Notified exemptions: banks/financial institutions/NBFCs, insurers, goods transport agencies (GTA), passenger transport services, admission to cinematograph exhibition in multiplexes, SEZ units (SEZ developers are IN scope), government departments and local authorities.
The 30-day IRN reporting window is a hard IRP validation, not a penalty: report late and you simply cannot generate an IRN, so the document is not a valid tax invoice and the buyer loses input tax credit. It applies to credit and debit notes too, which teams routinely forget. Threshold is tested on ANY FY from 2017-18 onwards — a one-off spike year permanently pulls you in; falling below ₹5 crore later does not release you. SEZ units are exempt but SEZ developers are not.
2 of 4 are primary sources. Mandate dates move — treat this page as a starting point and confirm against the primary source before committing a plan.
A page is a starting point. A scoped analysis gives you the specification, the mapping and the effort — in weeks, not quarters.