Firmware and Radio confutions

Hi All

hope someone can help. simply my question is I can see a newer radio version is out on my M8, so I wanted to find out how to update. turns out via the firmware package. Fine. Then not sure on what firmware package to use, so wanted to find what version i'm on so did a fastboot getvar all and the version main isn't showing? Anythoughts?

he is the details from getvar
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.24.21331147A1.09G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main:
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) serialno: SH43NW******
(bootloader) imei: *******************
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul
(bootloader) platform: hTCBmsm8***
(bootloader) modelid: 0P6B10000
(bootloader) cidnum: HTC__001
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: 3aa067db
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!

in setting the firmware is showing as 6.12.1540.4

The rom is Android Revolution HD 51.0

Thanks

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