1. Change Deferral method to None of all Account Types

UPDATE account_account_type SET close_method = ‘none’

2. Rename code of existing Account Types. This is to differentiate from the newly created account types
UPDATE account_account_type SET code = code || ‘-old’

3. Import your new Account Type with correct P&L / BS Category and Deferral Method (Accounting -> Configuration -> Accounts -> Account Types)

4. Rename existing account name. As explained it will help in filtering

UPDATE account_account SET name = name || ‘-old’ WHERE id IN (SELECT id FROM account_account WHERE user_type IN (SELECT id FROM account_account_type where code like ‘%-old’))

5. Import your new Accounts (Accounting -> Configuration -> Accounts -> Accounts)

6. Repeat Step 5 for other companies (in multi-company environment)

7. Import journal for each company with their default Debit and Credit Account. Specially, for Bank and Cash journals where these accounts are mandatory (Accounting -> Configuration -> Journals -> Journals)

8. Update Company Properties (Settings -> Technical -> Parameters -> Company Properties) to point to the right account like property_account_receivable, property_account_payable, property_account_expense_categ, property_account_income_categ, property_stock_journal and so on.