GST rules amendment updates UIN treatment, refund formulas, registration limits, and filing forms for specialized refund claims. Amendments to the Uttarakhand GST Rules, 2017 aligned UIN treatment with the Central GST Act, limited retrospective amendment of registration particulars, revised refund formulae and exclusions for zero-rated supplies and inverted duty structure, and inserted additional refund provisions for specified notified supplies and exports. The notification also updated filing requirements and substituted forms relating to registration, UIN refunds, quarterly inward supply statements, refund applications, and verification formats.