Problem
After upgrading Sametime Server, users using older versions of IBM Notes clients cannot login.
Cause
The default value for VP_SECURITY_LEVEL in Sametime is different. In version 8.5.1 is 7000. In earlier releases, this value was 25. This setting prevents any clients older and Sametime 7.0 from logging in. Notes 6.5, Notes 7.x and Notes Basic 8.x are all based on Sametime 6.5.1 code and therefore get locked out due to this setting.
Sametime 8.5.1 introduced a new setting to control the allowed client version separately from the server, ST_MINIMAL_CLIENT_VERSION. When unset it will default to the same value as VP_SECURITY_LEVEL.
See: https://publib.boulder.ibm.com/infocenter/sametime/v8r5/index.jsp?topic=/com.ibm.help.sametime.v851.doc/config/st_adm_comm_set_security_level_t.html
Resolving the problem
In the [Config] section of the sametime.ini section add ST_MINIMAL_CLIENT_VERSION=6510 (or lower) to resolve this issue.
Note that all servers in the environment must have the same values for both VP_SECURITY_LEVEL and ST_MINIMAL_CLIENT_VERSION to communicate with each other.
