Hello @Shaw, Bryan!
Welcome to Microsoft QnA!
Please have a look :
Open SQL Server Management Studio (SSMS).
Connect to your SSAS instance.
In Object Explorer, right-click on the SSAS database for which you want to change the compatibility level.
Select "Properties."
In the Properties window, navigate to the "Compatibility Level" property.
Change the value to "1500."
I hope this helps!
Kindly mark the answer as Accepted and Upvote in case it helped!
Regards