I have actually the similar question as well.
As I remember there was a download process, which after submitting download IDS (debug and water mark version), the corresponding SN was shown for later usage.
But for current CC 2018 download from Prerelease no SN is provided.
Anyone has information how can I get them?
I am a member of Technology Partners.
Thx for any help.
I see an "Serial number not required" next to the InDesign Server 2018 downloads.
Thx for your quick response.
As you can see from my screenshot, ESD is not visible to me.
But you clarified my question, that you did not get your IDS from prerelease.