Helma 1.5.0 was released on June 6. Expect a maintainance 1.5.1 release later this summer.
For Helma 1.6 (traditional Helma core with enhanced script libraries and running with Rhino 1.6), Marcello Bastéa-Forte has sent a patch that would preserve helma-doc app introspection with Rhino 1.6. The other option would be to disable code introspection and only support skin and properties file introspection in the Helma manage app for Helma 1.6. The area that needs possibly most work for Helma 1.6 is the Rhino debugger, which has changed quite a lot in Rhino 1.6.