Castle began as an attempt to bridge Avalon to .Net. Planning already is under way for version 2.0 of Castle. The MonoRail component in version 2.0 may be enabled to work with many view engines at the same time. A domain language to generate JavaScript also is eyed, as is a better template engine in the vein of Ruby. Performance improvements also are planned for MonoRail.

Initialization and mapping improvements are expected for ActiveRecord in Castle 2.0. The IoC (Inversion of Control) microkernel in Castle may be more configurable as well.