If you cannot access the digital download due to regional IP blocks, original update SD cards are sold physically. Search for: "Panasonic CN-MW200D 更新SD" (Kōshin SD – Update SD). Cost ranges from ¥10,000 to ¥25,000 JPY.
You can check the Panasonic Automation Controls Download Center for general manuals and technical guides, though specific car navigation firmware is rarely hosted here. panasonic cn-mw200d software download