Are you planning to upgrade core of the WinSCP Far Manager plugin to match current WinSCP's one?
There was a bunch of bug fixes and improvements (especially notable is introducing long awaited FTPS), so IMHO even from security PoV it deserves to be updated.
Bringing Far 2.0 fully compatible version (unicode, etc.) would be nice, but it's a secondary thing. So if you have some spare time, then upgrading core is much more important than upgrading Far scaffolding, which, I believe, will be done eventually anyway.