I'm aware that I can't update through the Windows Store, but can I update using an 8.1 RTM ISO somehow? What are my options? Currently running 8.0 RTM x64 Pro
Yes, you can upgrade the KMS activated 8.0 RTM to 8.1 RTM through ISO, but not from Store. But your Activation will not remain in this process. You will have to Activate Windows 8.1 again using KMS.
Thank you.. I've searched around a bit but couldn't confirm. Do you know the steps needed or can share a link to a thread?