The listing for FreeFileSync does note that it is not a recent version. It doesn't note that that means that major features (e.g. support for SFTP) that are prominantly described on the app's website are not included in the portableapps version. If the listing suggested an alternative that would be gravy.
"Later Versions Broken and Pay-For-Portable: All versions of FreeFileSync after 6.2 are broken and can't be run from other apps. This prevents packaging, use of the base portable version with menus like the PortableApps.com Platform, use of the local version with a scheduler, use of the local version with an alternative start menu, etc. Details are in this bug report from March 7, 2014 which the publisher did not address. The current version of FreeFileSync can not be used portably without paying a fee, is no longer fully open source, and may be in violation of the GPL."
Sometimes, the impossible can become possible, if you're awesome!