GW ist sich da leider selber nicht einig.
Folgendes ist alles aus der einen angegebenen Quelle:
https://www.warhammer-community.com...-questions-answered-july-5gw-homepage-post-2/
Can I combine units from the index and a codex into one army?
The datasheets in the new codexes overwrite the same datasheets in the index books. You can certainly use units with updated datasheets alongside units from the index that have yet to be updated. Once a unit has been covered in the codex though, we assume you’re using the latest version.
Can I choose to use the rules and/or points for units from my index instead of the new ones in the codex once released?
In your own games, if you and your opponent agree, you can, of course, play with whatever rules you like.
In all future publications and official events though, it will be assumed that you’re using the most recent rules and Datasheets. It will also be assumed that you’re using the most up to date points for matched play, in this case, those included in the codex.
There are a few options that are missing in the codex that appear in the index: why is that? Does that mean I can’t use these models in my army anymore?
While the indexes are designed to cover a long history of miniatures, the codexes are designed to give you rules for the current Warhammer 40,000 range. There are a few options in the indexes for some Characters and vehicles that are no longer represented in the Citadel range – certain Dreadnought weapons that don’t come in the box, or some characters on bikes, for example.
Don’t worry though, you can still use all of these in your games if you have these older models. In these instances, use the datasheet from the index, and the most recent points published for that model and its weapons (currently, also in the index).
They still gain all the army wide-bonuses for things like Chapter Tactics and can use Space Marines Stratagems and the like, so such venerable heroes still fit right in with the rest of your army.
Einerseit schreibt GW, dass man in privaten/eigenen Spielen machen soll was man möchte aber in offiziellen Spielen die aktuellen Versionen nutzen soll.
Andererseits wird genau auf die Cybotthematik eingegangen. Wobei hier nur "your games" verwendet wird und nicht "official events".
Ich würde es Begrüßen, wenn TTM entscheidet, dass es wie früher ist: nur die aktuellste Publikation gilt.
Ich konnte früher auch keine Modelle aus einem alten Codex spielen, wenn es im neuen keine Regeln dafür gab.
