Is the Hunter x Hunter 1999 version different from the 2011 version?

I've seen what Hunter x Hunter 2011 is out on Netflix. To be able to look further, I looked for full episodes on YouTube. I didn't find anything from Hunter x Hunter 2011, but from Hunter x Hunter 1999 there was almost the whole series. So what I want to ask is can I just keep watching after the third season of Hunter x Hunter (So the York New City Arc) in 1999, or did I miss something important if I didn't see the episodes before?

It's actually the same series, only the animation is a bit older.

OK thanks.

1999 only goes as far as Creed Island Arc and is older too. 2011 is a remake with two more arcs.

Not true, read my answer.

Different drawing style. The 1999 anime only goes as far as half of the 2011 episodes are purely from the manga adaptation.