LMS can be made to work with both SNMPv3 and v2c, but not on the same device. That is, given device A, you must choose whether or not you want LMS to manage device A with SNMPv3 or SNMPv1/v2c. There is no fallback in LMS from v3 to v1/v2c. Only configure one set of SNMP credentials per device. If you configure any v3 credentials for a device, LMS will opt to use v3 and ONLY v3 for that device.
However, given device B with device A managed with SNMPv3, if only SNMPv1/v2c community strings are configured for device B, LMS will only use v1/v2c to manage device B while happily managing device A with SNMPv3.
