Have I understood this correctly, does GMS2 really install itīs own
webserver when upgrading from GMS1? If thatīs the case, then what happens to
old SSL-certificate that has ben signed by trusted CA and which IIS uses to
all https traffic?

Do we have to purchase a new certificate for this new version/webserver or
does upgrade automatically notice that there is an old certificate installed
and that it should be used?

Trusted certificate costs few hundred bucks, so we are not very happy if it
needs to be purchased again to the same server just because of software

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