According to Antony Lesuisse (Odoo CTO) and his technical announcement to odoo community Odoo 9 will have two flavors (Community and Enterprise).
Odoo Enterprise will consist of Odoo Community plus a set of enterprise only
features (or in technical term, an additional repository with extra modules).
Some new features that have been under developement latetly will be in
enterprise such as electronic signature, integration with shipping providers.
For example the crm_voip module (currently published as a paid app on the app
store) will be in the enterprise repository. However core modules like the new
accounting remains in the Community version.
Odoo community will be supported as much as Odoo enterprise, Odoo Community is
the foundation of Odoo Enterprise and it will remain free and open source as LGPL.