The implication behind that email is that, a year or so ago, you (or someone using your email address) either bought an Adobe subscription plan or started a free trial of one of those plans. In the course of that episode some images were maybe stored in the cloud, and the email is advising you that the one year grace period is almost up and that you need to do something about that content or you will lose it. If you don't want to take out a subscription simply follow the instructions to use the Lightroom Downloader to download whatever images you have in the cloud. Of course, whatever you put up there may simply be copies of some of your images in your LR5 catalog, in which case you may decide that there's no need to do anything and the images can safely be deleted.