Listen Mode, file transfer missing

[mikeb]

Upgraded to 1.2.1.0 recently. I use VNC Single Click to access remote computers. I think the build I have in use is the 2009 SC, although it may be 2013. When clients reverse connect to me on 1.2.1.0, the file transfer button is not visible.

Is that because 1.2.1.0 is not compatible with the transfer in older builds of single click?
Is there a way to get legacy compatibility without downgrading the version?
Do I need to do a new build of Single Click to make file transfer work?
Is the 2015 single click builder the latest stable version?

I would prefer not to have to rebuild and distribute a new Single Click exe, as the old exe is already on a lot of machines out there. I can't update them remotely, and I won't know which ones need updating until I need to use it.