There is a file conflict between netifaces and python-netifaces packages in the winswitch repo for Fedora 20:

file /usr/lib64/python2.7/site-packages/netifaces.so from install of python-netifaces-0.10.4-1.fc20.x86_64 conflicts with file from package netifaces-0.10.4-1.fc20.x86_64

Both of netifaces-0.10.4-1.fc20.x86_64 and python-netifaces-0.10.4-1.fc20.x86_64 are in the winswitch repo, conflicting with each other.

It looks like the xpra package used to depend on netifaces but it depends on python-netifaces now, but python-netifaces is not coinstallable with netifaces.

My guess would be that the python-netifaces is missing Obsoletes: netifaces.

The Windows plink binary needs updating as it has very limited MAC algorithm support and newer Linux distros have disabled those by default.

Log connecting to an Ubuntu 15.04 server: sshd[27346]: fatal: no matching mac found: client hmac-sha1,hmac-md5 server hmac-sha2-512-etm@…,hmac-sha2-256-etm@…,umac-128-etm@…,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160 [preauth]