I wish I had kept a MetaLink and/or documentation article I ran across once that states that the listener major version should match the DB major version. And we did run into problems trying to have one listener dole out connections for both 8.1.7 and 9.2.0 DBs. So, using in part the explicit auto-registration techniques described here in another thread, we have separate listeners, running of course on different ports. HTH! GL! Rich -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Wolfson Larry - lwolfs Sent: Wednesday, May 24, 2006 11:27 AM To: oracle-l Subject: Listener with mixed releases Got a couple of clients who had us install 10G on some servers where some have DBs and some don't. The installers activated the 10G listener (because we always use highest version) and we got 1000s of oerr tns 12618 12618, 00000, "TNS:versions are incompatible" // *Cause: The two machines are running incompatible versions of TNS. // *Action: Check the version numbers, and upgrade the machine with the // smaller one. [snip] -- //www.freelists.org/webpage/oracle-l