Domino - XML (via Soap)

A Client needs to send domino data to vendor via XML stream (and receive back). Vendor wants it to be transmitted via SOAP.

I have read everything in Forum, LDD etc. It seems to be straightforward.

SoapConnect

LS or Java Agent

Automatically converts to XML???

Question: Client is currently on 5.11, upgrading to 6.5 in March. If the code is written for R5 will it still work in 6.5?

Any input would be appreciated,

Nicola