In legacy applications (those built prior to the release of VTScada 12.1), notifications carrying different usernames were accepted if they had the same credentials. For example, if you had specified three users: User1, User2, User3, then all these users would have the same credentials (the legacy credentials) and were all represented by a default username in the USM data base. Traps carrying any of the three user names were accepted.
Every SNMP driver now has its own sets of separate credentials, and therefore the legacy behavior does not apply unless this property is set to 1.
Default: SNMPDriverLegacyV3Notifications = 0
Section: System
