A fresh update is the perfect time to harden your device. Do not leave default settings.
Before jumping into downloads and updates, it is crucial to understand what firmware actually is. Unlike software applications that run on top of an operating system, firmware is low-level code embedded directly into the router’s hardware (flash memory). It controls the boot process, hardware drivers (4G modem, Ethernet ports, Wi-Fi chip), and the administrative interface. Dwr-m960 Firmware
The short answer is The DWR-M960 uses a proprietary 4G modem (often a Quectel or Sierra Wireless) with closed-source drivers. While the main CPU may be a MediaTek SoC that OpenWrt supports, the modem interface and GPIO pins for industrial I/O are not documented. Attempting to flash third-party firmware will almost certainly brick the radio module. Stick to official DWR-M960 firmware from D-Link. A fresh update is the perfect time to harden your device