Anyone know where to find the registration code to activate the online features?

Hi,
check in your account for the game "More" -> CD Key.
Worked fine for me.

Is that in the GOG client? There's no CD key entry in the "More" dropdown menu.

Here on the GOG website. Log in with your account data, display your games, click on "X4: Foundations" and select "More". There you'll find the "Serial Keys" (see attached picture). It is NOT ENOUGH to use the "down arrow" in the game list, you must select the game and click on "More".

Thanks found it! Apparently the serial number option shows up in the web browser only but not in GOG Galaxy.

Yes. Thank you very much. I found it now.

Would love to know that as well.

This worked thanks! :)

Thank you so much!

So GOG has this game yet it has DRM? Expensive and deceptive....

GOG promises DRM free for single player content. I guess this has to do with the now removed ventures thingy where you could get some unique ship paint jobs or other things you can get in the game by other means. Nothing stops you from doing your own paint jobs or get from other players.

About the price of the game: Yes, it is not cheap but it has a lot of game.

I don't think it has DRM right now. "Online features" (if one may call it that) are gone (and their re-implementation is not there yet) and all the content can be accessed via mods.

That being said, I'm against devs' plans to bar some content (unique ships) beside Ventures in the future.
Still cheaper than Stellaris. :)

I remember how some people back in the day was saying that online stores are so good becouse theres no need to move physical discs around and prices will get lower becouse of that. Now we have the game almost 3 years old have the basic price the same all the time and even on discount they still have the same price as many premiere games back in the day -.-

Keep in mind that once you've registered you get access to DRM-free executable:
https://www.egosoft.com/download/x4/bonus_en.php