How to install "2019 Edition" over the old "theHunter 2017"

[76561198056596934]

I've bought the Hunter 2019 Edition (german DVD version), from a local store today. It says all DLCs up to the release day (Oct 16 2018) are included.
Anyway the DLCs didn't appear.
Can someone tell me how to install the game properly ?
I've tried by now:
1st -The reinstall option over the existing older version.
2nd - I've deleted the older version from Steam and then I installed the new one from DVD.
Nothing worked. The game is running but just the basic game without the DLCs.
Also there was no request to enter the new Steam key for activation after the installation process.

Can someone help please ?

[PicSoul]

Sorry, I'm not sure how the upgrade process would work. I'd recommend contacting Support.

theHunter Support [support.thehunter.com]

[Woodyplank]

The Duck DLC in not included.

[76561197987696714]

Why don't you just activate the key in steam and all the dlc in the 2019 edition will unlock for the 2017 edition because thats what it basically is.