I think this is was a bad update strategy. If I am getting this correctly, I can only install v6,x from the MS Store if I have Win10 (Win7 machines are not able to download as they won't show up on the list of devices). Given that v6.x CAN sync to cloud, but v5.x (which is install-able on Win 7 machines) CANNOT sync to the cloud., then it seems like a big disconnect here. You've just made all of your users who are on Win7/8 (by choice) unable to install a version on their desktops and really be of any use. I run a mixture of Win 7 & Win 10 machines, but my favorite is definitely Win 7 and am going to keep Win 7 around for quite some time on them.
I do think this strategy is somewhat flawed and it does have me looking for something better to fit my needs...