Critical Description
The 4.0-beta-8 codebase says that Body.get(cycle) is deprecated but the current implementation simply throws an exception, breaking my old 3.0 components which use it. Specifically it passes in null as the component parameter which is then asserted to be not-null inside TapestryUtils.getPageRenderSupport(...). There is no workaround since the "use instead" javadoc for Body.get(cycle) is old of date - getPageRenderSupport(....) now takes two parameters and it is unclear what to pass in as the second "component" parameter.
I'm marking as critical simply because this method is no longer usable and there is no documented workaround.