rsync 3.1.0 on Ubuntu 14.04 has a bug that causes an error when coming from rsync 3.0.9 (common on all versions of Ubuntu prior to 14.04)
Hi Simon, could you open an issue for this on github? Thanks!
“Synchronize module does not work going TO Ubuntu 14.04 from anything older than Ubuntu 14.04”
See http://rsync.samba.org/issues.html and search for “io.c”