is the 4G LTE-capable version designed for specific GSM networks. How to Find and Update Firmware

Firmware for the Q5 includes:

While over-the-air (OTA) updates may no longer function reliably due to decommissioned servers, there are still ways to manage the device's software:

Since the official BlackBerry infrastructure has been decommissioned, the most critical "paper" information you need for managing this firmware includes: Technical Specifications & Firmware Logic

Before tinkering, back up your current firmware. While you can’t dump the whole NAND easily, you can: