I was doing similar for Linux, from 7.1.1 to 8.1 last night.
Linux docs are very clear - you have to pick the update option.
Most likely same thing for Windows

On Wed, May 10, 2017 at 4:27 AM, rouzen AT univ.haifa.ac DOT il <
rouzen AT univ.haifa.ac DOT il> wrote:

> Hi to all
>
> I am now in TSM server version 7.1.7.100 on O.S Windows 2012 64B.
>
> I download the version 8.1.1.0 from passport advantage .
>
> The document said to choose the option INSTALL if moving from version
> 7.1.7 + to version 8 +
>
> Here from documentation page: 83
>
> Installing V8.1 and verifying the upgrade To complete the process of
> upgrading the server to V8.1, you must install the V8.1 server. Then,
> verify that the upgrade was successful by starting the server instance.
>
> I run the INSTALL option but got this error message:
>
> Package IBM Spectrum Protect server is already installed. Only one
> instance of this package can be installed.
>
> To install a later version of this package , click OK , then return to
> Start page and select Update .
>
> I will open a PMR , but in meantime any advice will be appreciate
>
> Best Regards
>
> Robert Ouzen
>
>


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