Squeak 3.9 is the current work-in-progress development release.
The 3.9 release has its own mini-mailing list. Feel free to join or follow the archives here.
You can create a 3.9 alpha image from a 3.8 final image. Just evaluate:
SystemVersion setVersion
and enter Squeak3.9alpha, and perform an update.
Here is a tentative release plan for 3.9, still being worked on (see TODO3.9):
Monticello (Essential for the new Packages+Update Stream process.)
ToolBuilder This is the inclusion of ToolBuilder itself and also the conversion of all hardcoded references to PopUpMenu etc to use the more generic ToolBuilder code instead. (Göran Krampe: The idea is to make sure it gets in so that tool maintainers can migrate over to ToolBuilder during and after 3.9, in order for the tools to work in other UI frameworks in post 3.9 releases where Morphic isn't necessarily around anymore)
Partitioning of something into a package would not necessarily mean removal from the 3.9 Basic configuration
The PackageInfo-Extras package may be needed in 3.9 for dealing with PIs. (Göran Krampe: Well, I would say it is a "very good thing" to have, not just "needed". :) This is because it offers "changeset splitting" and "mail to maintainers" mechanisms in the changesorters, which are the equivalent of "mail to list", but in a partitioned world)
(The Morphic Splitters team will be working on splitting off a Morphic package, which will likely be an installable filein for 3.9, but won't actually be incorporated until immediately after 3.9.)
Medium-sized & miscellaneous grab-bag enhancements to be considered, listed here as a reminder.
A Services framework (to let any type of service register itself without having to modify base methods). Consider Romain's if the implementation is solid/ready.
Keybindings or Keymapping (different frameworks, similar ideas)