Anyone using Domino Admin client R7 in a mixed R6.5/7 environment?

All of our clients are R6.5 right now, but we want to start testing any changes for a possible R7 client release. There are also colleagues that are interested in getting their certifications upgraded for R7 before the end of the year.

So does anyone know of any issues with R7 clients accessing R6.5 Domino Servers? Oh, and before you ask, we are in the process of upgrading our servers to R7, but it may not be until January 2009.