They are. The cheapest server plans and ipv4 floating IPs are affected by this change. The FAQ only covers the root servers part though.
The marketing page [1] still lists the same €2.49 + VAT /month price for the cheapest CX11.
Product. Price per month / hour up until now Price per month / hour, effective 1 Sept 2021
CX11 2.49€ / 0.004€ 3.49€ / 0.0055€ CPX11 3.49€ / 0.006€ 3.99€ / 0.0065€
Still, it sucks to pay €1.00/mo for an IPv4 address I don’t want or use.
Also, they should update the marketing site to clearly show the impending price change.
Edit: they’ve updated the website.