An upgrade from 6.x to 7.x fails with 'Nothing to do' if you are using a yum package manager as Yum does not recognise 7.x as an upgrade over 6.x when a specific version is used from yum repository.
$ yum install jfrog-artifactory-pro-<version> Nothing to do.
This is because there was a change in architecture between 6.x to 7.x artifactory rpm. It was changed from "noarch" to "x86_64".
Please note: This behaviour is not seen when we try to upgrade from 7.x to 7.x as the architecture is same.
To get past this you can download the artifact and upgrade using rpm,
yumdownloader jfrog-artifactory-pro-<version> rpm -Uvh jfrog-artifactory-pro-<version>.rpm
Note : yumdownloader is part of yum-utils i.e. you may need to install yum-utils before
yum install yum-utils