I'm updating my original post. I have located the January 2019 version of the Desktop app, and that appears to support the Report Server. I can now see the Report Server and open reports stored there, but when I attempt to save a report to the Report Server, I get the following errors. Any help would be appreciated!
2019-02-28 13:22:05.9589|ERROR|17|Failed to publish model for temp_48b4e070-6c65-400e-9663-f110bc5cd7ec| RequestID = s_504ee3aa-a5a4-4c80-9d14-1e47aa89c09a Microsoft.PowerBI.ReportServer.AsServer.AsConnectionException: Failed to publish model for temp_48b4e070-6c65-400e-9663-f110bc5cd7ec ---> Microsoft.AnalysisServices.OperationException: 1465 is not a valid value for this element.
An error occurred while parsing the 'ddl200:CompatibilityLevel' element at line 1, column 2452 ('http://schemas.microsoft.com/analysisservices/2010/engine/200' namespace) under Load/ObjectDefinition/Database/CompatibilityLevel.
An error occurred when loading the 'temp_48b4e070-6c65-400e-9663-f110bc5cd7ec', from the file, '\\?\C:\Program Files\Microsoft Power BI Report Server\PBIRS\ASEngine\workspaces\750056618.1.db.xml'.
at Microsoft.AnalysisServices.XmlaClient.SendExecuteAndReadResponse(Boolean skipResults, Boolean throwIfError, Boolean useBinaryXml)
at Microsoft.AnalysisServices.XmlaClient.ImageLoad(String databaseName, String databaseId, Stream sourceDbStream, Boolean allowOverwrite, String readWriteMode)
at Microsoft.AnalysisServices.Core.Server.ImageLoad(ImageLoadInfo imageLoadInfo)
at Microsoft.PowerBI.ReportServer.AsServer.AnalysisServicesServer.<>c__DisplayClass17.<LoadDatabaseInAsAsync>b__16()
--- End of inner exception stack trace ---
2019-02-28 13:22:05.9589|ERROR|32|Failure in reportproperties| RequestID = s_504ee3aa-a5a4-4c80-9d14-1e47aa89c09a Microsoft.PowerBI.ReportServer.AsServer.AsConnectionException: Failed to publish model for temp_48b4e070-6c65-400e-9663-f110bc5cd7ec ---> Microsoft.AnalysisServices.OperationException: 1465 is not a valid value for this element.
An error occurred while parsing the 'ddl200:CompatibilityLevel' element at line 1, column 2452 ('http://schemas.microsoft.com/analysisservices/2010/engine/200' namespace) under Load/ObjectDefinition/Database/CompatibilityLevel.
An error occurred when loading the 'temp_48b4e070-6c65-400e-9663-f110bc5cd7ec', from the file, '\\?\C:\Program Files\Microsoft Power BI Report Server\PBIRS\ASEngine\workspaces\750056618.1.db.xml'.
