SparkPost is discontinuing its Message Events API from October 1, 2019. The Message Events API allowed the Email Experience Manager (EXM) to provide Email Delivery Cloud customers with visibility into open and click rates, unsubscribe statistics, and more. The discontinuation of this API might cause customers to see empty statistics in their email campaign reports. Specifically, this affects users of Sitecore XP from 9.1.0 to 9.3 who will no longer be able to see recipient activity data in EXM.
To resolve the issue, consider one of the following options:
Be aware that the hotfixes were built for the specific Sitecore XP versions and must not be installed on other Sitecore XP versions or in combination with other hotfixes. In case any other hotfixes have already been installed on a certain Sitecore XP instance, send a request for a compatibility check to Sitecore Support.
Note that you must extract the ZIP file contents to locate installation instructions and related files inside. You must install the hotfix on a CM instance and then sync it with other instances using standard development practices.