How do I update?

[Kerbface]

I don't see a link anywhere. I went into the game and clicked the check for updates button (a whole lot of times) but it doesn't do anything at all. I have 0.19, never updated before.

[GJames]

You have to go to the KSP Store (should be along the top of the website) and log in. Then clock on the "profile" button below the username and password boxes. It should be fairly straightforward from there.

[EndlessWaves]

The check for updates button is disabled until the new patcher is finished, once that's done you should be able to update an existing clean install rather than downloading the new version from the store.

[georgTF]

Yes, basically download the new version from the store and unzip it in a new folder. You can keep playing the old game or play the new version. I'm not sure to what extent mods or registry entries will affect multiple versions but i haven't run into any problems so far.

[Kerbface]

How do i transfer my old data across?

[EndlessWaves]

How do i transfer my old data across?

Copy your save folder across.

While the game is in development there's a good chance it won't be compatible with the new version but in this case I hear there aren't many problems.