After the device reboots, you can verify the current version: About phone System Update
Go to Settings > System > System Update and tap Check for Updates . This is the safest way to get the latest security patches.
Firmware (also called stock ROM) is the low-level software pre-installed on your phone’s internal memory. It includes the Android operating system, the TCL UI layer, device drivers, and system partitions like boot, recovery, and modem.