The requirement to create an Opening Entry has been removed from Odoo at v9 in order to simplify the user experience; to have users able to review correct reports without needing to reply on specialized accounting expertise; and to allow users to work without worrying if the previous year was 'closed'.
Profit and Loss Accounts don't have to be reset.
Balance Sheet Accounts don't have to be brought forward.
Current Year Earnings are computed automatically.
Several things have been implemented to this end.
1. You can set the "Fiscal Year Last Day" in Accounting --> Configuration --> Settings.
The opening account balances will be computed automatically (carried forward or reset) based on account type and this date. This is done without actually creating a Journal Entry to change balances. It is only at the reporting level, not at the general ledger level. For Balance Sheet accounts, the computation starts from the first day data was entered into Odoo. For Profit and Loss accounts, the computation is based on the start of the new fiscal year.
2. On the balance sheet, a virtual calculation (not stored in the general ledger) for 'CURRENT YEAR EARNINGS' is computed.
This is also based on the Fiscal Year Last Day. This is the sum of all Journal Items with an account on the Profit and Loss statement from the first day data was entered into Odoo.
3. To close a year:
1. Allocate the Current Year Earnings amount (for the year to close, the previous year) to "Undistributed profit/loss" or your renamed "Current Year Earnings" account.
2. Verify Current Year Earnings is $0 for the current year, or is correct if you have already started transactions.
3. Set the Lock Date to match the last date of the Fiscal year so no changes can be made.