I can't find any specific information about 23C Release.
I only checked the URL below for brief information about 23C Release, but I can't confirm what changes are made specifically.
In particular, the contents related to the Salesforce App must be tracked as the project is currently underway.
Could you give me the URL related to the release details?
And I checked the contents of Bulk API regarding 23C release, and this part needs to be checked as well.
What kind of app are you talking about in Eloqua?
Does the Salesforce Integration App also apply?