Upgrade OS question

Hi everyone,
I’ve got a turris omnia since 2017/2018 and today I’m asking myself to upgrade the firmware to another version. But i’m a bit lost about OpenWRT and Turris upgrade. This is my first router.
I want to upgrade my Turris if it possible to a newer version. I checked the documentation https://docs.turris.cz/basics/tos_versions/ to find my os version but I’m a bit lost. I found my OS version on Foris, it’s actually 3.11.16
But it look like in Luci I’m using OpenWrt omnia 15.05 r47055 / LuCI fd63d5cc7dfc69c640b741dceb80555141a80670 branch (git-19.318.61483-fd63d5c)
I checked on the OpenWRT project and it’s look like there are a 19.07.x version available.
Why actually I’m still using an “old” version 15.05 ? Why on the documentation we can saw on the screenshoot a 4.0.1 version available ?
Do I need to perform a sysupgrade manually to upgrade my os version to 18.06 / 4.X.X ?
I see some issue with the latest 19.07.02 Bricked Turris Omnia: After Turris OS 5.0 -> sysupgrade OpenWRT 19.07.2
Actually I think to upgrade to Turris OS version 4.X.X version if it’s possible. But how can I do this ?
If someone can help me to figured out.
Thanks you


I have already answered the same question in different thread. Take a look here:

Sysupgrade is not present in Turris OS 3.x release and will be removed in Turris OS 5.0. It is dangerous and it shouldn’t be used as Turris routers are automatically updated.

If you would like to have Turris OS 5.x, which is based on top of OpenWrt 19.07, I suggest to take a look in this thread:

Closing as this is duplicate.