How does the KOR small-seller scheme work in Magento?

The Kleineondernemersregeling (KOR) exempts Dutch businesses with under €20,000 in annual NL revenue from charging BTW. If you opt in, you don’t charge BTW, can’t reclaim input BTW, and can’t show BTW on invoices — instead invoices must say "vrijgesteld van BTW vanwege de kleineondernemersregeling". In Magento this means: (a) tax class “None” on all products with a 0% rate, (b) invoice template that omits BTW lines and shows the KOR-exemption note, (c) checkout that doesn’t display "incl. BTW" anywhere. If you cross €20,000 mid-year you must register for BTW immediately and start charging from that day — we add a Magento dashboard widget that warns when revenue approaches €18k.