How to update rooted S-off m7 to latest firmware?

Hello,
I have rooted and S-Off M7 (801n) that hasn't been updated for a very long time. It currently has kitkat. My goal is to install Revolution HD 93.0, ElementalX, TWRP and lastest firmware (inc. hboot and radio), which is I believe 7.19.401.51?

I know how to install ROM, kernel and recovery but my biggest concern which I am seeking help for is firmware. I found THIS but I read it's not recommended to skip FW and go to latest one directly as hardbrick can ensue. So I would probably need to install each firmware that was released between mine and latest 7.19.401.51? However I don't know where to find them or what version they were. Or would be easier to just apply some RUU or even go completely stock apply OTA and after that root and S-Off again?
How do I proceed? Can anyone please help?

Here is result from getvar all:
C:\Program Files (x86)\Minimal ADB and Fastboot>fastboot getvar all
(bootloader) version: 0.5
(bootloader) version-bootloader: 1.57.0000
(bootloader) version-baseband: 4T.29.3218.08
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 6.09.401.5
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) serialno:
(bootloader) imei:
(bootloader) meid: 00000000000000
(bootloader) product: m7_ul
(bootloader) platform: HBOOT-8064
(bootloader) modelid: PN0710000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 4106mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: dirty-6d8a0b9b
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
all: Done!
finished. total time: 0.187s

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