Posted June 24, 2016
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The "GOG XX" ist just another way to neme the version of the installer or the patch (GOG 21 = 5.1.1).
If you download the intaller ot the game now and use the you have the newest version which includes all books.
If you already have installed an older version on your PC you need to apply a patch.
5.1.1 is newer than 5.0.3, 5.0.3 adds the fifth book and 5.1.1 seems to fix a few bugs.
On the first line in above paragraph, did you miss typing in a word? You said "if you download the installer of the game now and use the ? you have the newest version which includes all books." -were you going to type in "use the ( latest) patch"? Thanks.
If you're not sure how to do it or in which order to install the patches (usually it is mentioned which version of the game is required to use the patch here it's not unfortunatly):
Deinstall the game (you get an option to keep your savegames) and reinstall it with the new game-installer and you have the newest version with sll 5 books.
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