Thank you for your patience while we continue working on our Bulk Asset Import module (using xlsx files for custom attributes). To ensure the best solution we are still finalizing some details and expect to have this re-enabled some time early/mid this week. We will share an update once the feature has been reactivated.
In the meantime, you are able to load .txt files with Standard Attributes, as you've traditionally done. If you need assistance loading the template please reach out to ClientSupport@ServiceChannel.com
and one of our agents will be happy to assist.