We have used ZSyncer for 2 years without problem. But, suddenly, it stopped working -- with an obscure "expat: not well formed exception". German special characters turned out to cause this problem. XML-RPC has a big problem when it should work with a both non-ASCII and non-Unicode site as it does not handle encoding of string data (especially, if it does not know the implicit encoding). When we have installed "PyXML" (to get expat, to use "text/xml" with PageTemplates), the "expat" parser started to complain about these non UTF-8 encoded characters. The formerly used parser apparently just ignored such issues. This is the second time that I got bitten by XML-RPC (its sensitivity with respect to "string" data).. I am now convinced that XML-RPC should not be used for Python-Python communication. I made a ZSyncer variant that uses ZPublisher.Client as RPC protocol and Python's "pickle" to marshal data. This gets rid of XML-RPC. If anyone is interested, let me know... -- Dieter