Aprilia dont want to freeze development until the first race of the year while all the other manufacturers have agreed to freeze development. Aprilia and KTM have concessions, which means development is not frozen at the start of the season

https://www.speedweek.com/motogp/news/158595/Hersteller-Buendnis-Wegen-Aprilia-fliegen-die-Fetzen.htmlhttps://www.speedweek.com/motogp/news/158595/Hersteller-Buendnis-Wegen-Aprilia-fliegen-die-Fetzen.html http://img.speedweek.com/i/5/58032505a37c48b1a571574601329838.jpg?preset=i750