Enforce mandatory Dutch invoice fields (KvK, btw-id, OB-nummer, sequential numbering, verlegd wording) with a pre-send validator and KvK/BTW format check.
Dutch second-hand goods margin scheme (margeregeling): individual & globalisation methods, margin book and margin-VAT computation.
Map the Odoo chart of accounts to the Dutch RGS reference scheme and export RGS-tagged ledgers for accountants and banks.
Dutch reverse-charge (verleggingsregeling) rule engine: detect construction/staffing/scrap & intra-EU cases, set the right rubriek and add the legal invoice mention.