After upgrading all custom MDX OLAP calculations within Cubes reports have disappeared

Upgrading Cubes server and all custom MDX (OLAP) calculations within Cubes reports have disappeared once the new connection is established

Cubes

Upgrading Cubes server

This is an Excel / Microsoft issue:

Note: Because the Excel MDX Calculated Measure is used to create a session specific calculation for a SQL Server Analysis Services data source, your Calculated Measure will be limited to the session and the data source connection you used.

If a connection file needs to be changed (e.g. new server requires updating the connection file), it changes the data source so those MDX (OLAP calculations) would need to be recreated.