NotifyLink Enterprise Server:

NotifyLink Enterprise Server error logging is intended to be used as a diagnostic tool by Technical Support staff.  Files may be set to log varying degrees of detail as needed or logging may be disabled in accordance with security laws or policies.

Servers where the logs reside should, of course, be secured.  In addition, when logging is enabled, administrators should limit access to the directory where the logs are contained.

A further security measure would be to limit the amount of information sent to the log files by reducing log levels.  Logging is enabled and set at level 2 by default. The log levels can be adjusted, however, to levels 0 through 4 (4 logs the highest level of detail; 0 logs only errors).
 
You may wish to reduce the logging level to 0 (errors only) in database files containing potentially sensitive user information:
In the database, set GeneralConfig.DebugLogLevel to 0

You may wish to totally disable logging in the registry:
In the registry on the HTTP/Web component server, set
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES AirSyncServer\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES InternetMsgService\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES ValidateLeaseService\EnableLogging to 0
In the registry on the Messaging component server, set
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES AttachmentService\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES AvailableUsers\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES GleanerController\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES NotificationController\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES PIMService\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES ResponseHandler\EnableLogging to 0
HKEY_LOCAL_MACHINE\Software\Notify Technology Corporation\NLES SyncMLServer\EnableLogging to 0