Since Avid dropped the 32-bit RTAS plug-in format and moved to the 64-bit only AAX plug-in format in Pro Tools 11, many plug-in developers have been working hard to bring their products to the new platform. Few have been more greatly anticipated than Waves, who have around 140 active products. Upgrading to AAX is free to Waves users who have an up-to-date Waves Update Plan. If you aren't covered, you will need to purchase coverage, and pricing depends on how many plug-ins you own.
Here's more from Waves:
Press Release: Following the release of Avid Pro Tools 11, Waves Audio is pleased to announce its support for the AAX Native plugin platform. Waves has consistently strived to support as many plugin platforms as possible, including VST, RTAS, TDM, AudioUnits and others. With this new development, Waves Native plugins are now fully compatible with the AAX platform, also used by Avid HDX systems.
Gilad Keren, Waves CEO and co-founder, stated, “AAX Native support has been a frequent request by many users. We are happy to respond to market demand with this new compatibility.”
"The portfolio of processors offered by Waves is among the most respected in the world," remarks Ed Gray, Director of Partnering Programs for Avid. "They are a most welcome addition to the AAX platform, and great news for users of Pro Tools 11. We are grateful for this support.”