We use various tools and scripts to watch the network to make sure things don't change "mysteriously" (aka nefariously). Ran into something the other day that we cannot locate an answer for.
We upgrade IOS on a 3650 and a PID changed on the sh inv display. It is a single device and the serial numbers did not change. It is the PID for the stack, so maybe it changed because of a stack change in the past on the device, but we don't think so. What ever the cause, we would like to know why, and understand how, the PID changed. [WS-C3650-24PDM changed to WS-C3650-24PDM-S]
sh ver
<snip>
Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
* 1 28 WS-C3650-24PDM 16.3.1 CAT3K_CAA-UNIVERSALK9 INSTALL
<snip>
sh inv
NAME: "c36xx Stack", DESCR: "c36xx Stack"
PID: WS-C3650-24PDM , VID: V01 , SN: FDO2033V0C7
NAME: "Switch 1", DESCR: "WS-C3650-24PDM-S"
PID: WS-C3650-24PDM-S , VID: V01 , SN: FDO2033V0C7
<snip>
sh ver
<snip>
Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
* 1 28 WS-C3650-24PDM 16.3.5b CAT3K_CAA-UNIVERSALK9 INSTALL
<snip>
sh inv
NAME: "c36xx Stack", DESCR: "c36xx Stack"
PID: WS-C3650-24PDM-S , VID: V01 , SN: FDO2033V0C7
NAME: "Switch 1", DESCR: "WS-C3650-24PDM-S"
PID: WS-C3650-24PDM-S , VID: V01 , SN: FDO2033V0C7
<snip>
