The client version does not match the server version

Hello,

I have an installation of NAV 2015. For testing purpose I have multiple Build version installed on the same Server / Client.
This configuration works except two components.
1) The Excel Add-In

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Microsoft Excel
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Microsoft Dynamics NAV Excel Add-in encountered an external error: The client version does not match the server version. You can only connect to a server with a matching version.
Client version: 8.0.39663.0
Server version: 8.0.41370.0
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OK   
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2) Administration Shell

Import-NAVServerLicense : The client version does not match the server version. You can only connect to a server with a matching version.
Client version: 8.0.41370.0
Server version: 8.0.39663.0

Did anyone know, what is to change, to have the possibility to work with different Build Version of the Excel Add in and the Administration Shell?

Thanks in advanced
Jeannot