Howdy, I'm starting an ERP DB upgrade from 10.1.0.5 to 11.2. One of my concerns is possible compatibility issues for the apps being able to use a new 11.2 client, which may or may not be certified for the various programmatic arms of our ERP. So I'm considering an option to leave all/some of the clients at v10.1.0.5. Is anyone using this config? Any issues? The interoperability matrix (MOS 207303.1) doesn't list anything specific as far as I can tell. There is no version-specific SQL we're using, but we do use multibyte NCHAR columns instead of CHAR/VARCHAR2, if that matters (NLS AL16UTF16). TIA! rich -- //www.freelists.org/webpage/oracle-l