I was unable to get the 7.7.251 interface to connect to my 7.0 store to do a store download. I was prompted for connection info and then received the version mismatch message and was unable to proceed.
I am fairly certain that I followed the directions correctly. The version mismatch message said the the version on the site (7.0.13700.0) was not compatible. That is the same version of the api.dll file in the 7.0.0 folder of the dataport download. So that seems to be a conflict.
I was able to connect using the 7.4.238 version in the archive folder on the ftp server and I am currently running a store download with that as I type this message. Followed the same installation steps so I obviously did that correctly.