Stuck with custom Rom - need some update help please

Hello Everyone!

I have problem with my HTC m8 and started to read in the forums, but could not figure out how to solve it.
Because:
Im using an old custom rom viperOne 1.8, on android 4.4.2 have S-ON and have an old TWRP 2.7.0.0 - (newer versions where just stuck on "Entering recovery...")


If i understood it right i have to upgrade the firmware, but i cant because of S-ON, tried Sunshine but it says "sunshine cannot function on devices which are set to debuggable".
So, if no S-OFF, cant do firmware update and cant get the latest rom etc. right?
Wanted to install the SkyDragon+M8+v+10.2+Sense+7 ROM and a firmware.

Could someone please tell me how to proceed or at least point me to the right direction?
(I would be really thankful for some exact versions or links to a file i have to use, not just like "you need to flash a stock firmware")

Some details:
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.16.0.0000
(bootloader) version-baseband: 1.16.2133156.UA10G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main:
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno: XXXXXXXXXXXXXXXX
(bootloader) imei: XXXXXXXXXXXXXXXXX
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B10000
(bootloader) cidnum: T-MOB101
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: c3d94491
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0


Thanks !