I'm trying to install Lightroom 6 upgrade but the version of Lightroom 4 that I am using was purchased on Apple ITunes and so there is no serial number to insert for the older version.
Hi Allan. This is possible, but you will need to contact Adobe Support. When you do, please reference this article: https://helpx.adobe.com/lightroom/kb/upgrade-mac-app-version-lightroom.html As long as you reference that article, Support will know what to do.
Thank you so much. I did contact Adobe Support 2 days ago via livechat and was told by the tech that my problem was "accelerated" and I was given a ticket number but so far no response.