Hi,

Odoo13 is expected to release by this October during the Odoo experience. There are lot of changes coming in the Odoo13. The website form  builder module which was part of enterprise edition was moved to the community in v13. You can see its working here in this video: Odoo13 Website Form Builder Moved To Community Edition

Regarding the accounting in Odoo13, there is no more account.invoice model in odoo13. account.invoice model get merged with the account.move, you can see it here: No account invoice Model in Odoo13

Sum up of Odoo13 Features: https://www.youtube.com/watch?v=NLbYN3R07to

Moved to Community From Enterprise:

* Website Form Builder

* Sales and Coupon

Moved to Enterprise:

HR Payroll: There will be no HR Payroll in Odoo13 Community edition.

New Apps:-

* Rental

* Approval

* E learning

* Employee Skill Management

* HR Presence

* Referrals

* Field Service Management

New Widgets:

* Calculator Widget

* Multi Company Widget

In Portal:

* Add attachments in portal

* Time-sheet in Portal

Also there are a lot of new features added in odoo13:-

1. Leave is renamed to Timeoff

2. Approval App

3. New Ribbon Widget in Odoo13

4. Sales Coupon and Promotion Program in Odoo13

5. Product Grid Configurator in Odoo13

6. Employee Skill Management

7. Optional Field Visibility

8. List View Improvements

9. New 'Buy Now' Button in Ecommerce

10. New Elearning App

11. Referrals App In Odoo13

12. Report Configurator In Odoo13

13. Odoo13 NEW Partner Map View

14. Lunch Enhancements in Odoo13

15. Field Service Management in Odoo13

16. Employee Presence New App

17. Inventory Valuation by Location is back

18. New Rental App in Odoo13

19. New Multi Company Widget in Odoo13

20. Improved Calendar View in Odoo13

21. Odoo13 Add Attachment Option in Portal

You can check more features here in this YouTube channel :  Odoo 13 Features

Also check this already asked question in the forum:  Odoo 13 features

Thanks