New Expansion Announced - Shadowlands
Blizzard have announced that if you pre-order the digital version, but then buy the CE version, they will credit your Blizzard balance with the original cost of your digital pre-order. Do note that this is based ONLY on the first version you buy - so if you buy the base, but then upgrade, THEN add the CE .. you will still only get credit for the initial purchase.
This is their post on the US forums - I'm assuming it will turn up on the EU ones when they get out of bed :p
We have seen some questions about how upgrades will work for the different versions of Shadowlands. While the process is similar to the last expansion, we want to take a moment to clarify how upgrades will work for some of the most common situations.
Upgrading from Any Digital Version to Collector’s Edition
If you purchase any digital copy of Shadowlands (Base, Heroic, or Epic), and then upgrade to the Collector’s Edition in the future, we will automatically credit you the cost of the digital copy in Blizzard Balance - as long as you enter the Collector’s Edition key before a future deadline. When you enter the key from your Collector’s Edition, we will see the original transaction on your account and the credit will be added. We will have details on this deadline when we have more information to share regarding the Collector’s Edition.
Upgrading from Base Edition to Heroic or Epic Edition then to Collector’s Edition
If you purchase the Base Edition of Shadowlands, then upgrade to the Heroic or Epic Edition, and THEN upgrade to the Collector’s Edition, your Blizzard Balance will be the price you paid for the original Base Edition.
Upgrading from Heroic to Epic Edition then to Collector’s Edition
If you purchase the Heroic Edition of Shadowlands, then upgrade to the Epic Edition, and THEN upgrade to the Collector’s Edition, your Blizzard Balance will be the price you paid for the original Heroic Edition.
Upgrading from Base Edition to Heroic or Epic Edition
If you purchase the Base Edition of Shadowlands, you will be able to upgrade to the Heroic or Epic Edition for the difference in cost between the versions.