As far as I know, there is no specified release date yet. Some of the AOLserver Core Team members guessed mid-May during the chat on March 13th, but they stressed that date was unofficial and the ACT hadn't discussed it as a whole. There should be an update in today's chat.
The current AOLserver 4.0 betas have full support for virtual hosts and internationalization in the core modules - a few non-core modules might need updates. (Don has already updated nscache.) More AOLserver 4.0 testing and bug reporting with OpenACS, dotLRN, and i18n specifically would be terrific, if you have time - the more bug reports and patches people submit, the sooner it can be released! I'd say the betas are definitely stable enough for development and testing purposes. I also believe AOL has started stress-testing it internally.
