It's possible to setup a 1.7 write-through proxy to a 1.6 master. This works provided that the 1.7 proxy uses "SVNAdvertiseV2Protocol off", but if the proxy doesn't disable V2 it forwards V2 requests to the V1 master which results in ugly errors:
svn: E175002: Commit failed (details follow): svn: E175002: Server sent unexpected return value (500 Internal Server Error) in response to POST request for '/repos/asf/!svn/me' I'm not familiar with the proxy code. I think a V2 proxy should check whether the master advertises V2 support and return a more intelligible error if it does not. I suppose it only needs to do this if the client is using V2 write commands, as a client using V1, or V2 read-only, will work fine. I suspect it is not possible for the proxy to switch to V1 automatically since I think the V2 support negotiated before the proxy contacts the master. Perhaps this is a valid use for the mythical "use V1" client switch :) -- uberSVN: Apache Subversion Made Easy http://www.uberSVN.com
