The SNMP version/profile is determined during the initial inventory discovery.
Once it is determined, the SNMP profile won’t be changed unless the profile no longer works (as in we stop getting
SNMP responses from the device during poling or rediscovery)
When the SNMP profile stops working, there are two ways that the SNMP profile would be re-evaluated.:
1) Re-run inventory discovery;
2) After waiting for two poll cycles, SNMP profile discovery will be automatically invoked.
Additionally we always choose SNMPv2c over SNMPv1 unless the SNMP test with SNMPv2 fails.
The SNMP version is part of the profiles therefore is evaluated at the points above.