Would shutdown of secondary node trigger an election

As per the notes, any change in TOPOLOGY will trigger the election. And following are the factors that result into topology change
1)adding members to set
2)failing members (could you please elaborate on this?)
3)changing in replica set configuration

So my question is if we shutdown the secondary node(db.shutdownServer()) or kill the process of secondary node for rolling upgrade, would it trigger an election?

Yes, that’s a topology change.

But because I can be wrong and it may be useful elsewhere, you can check the server status, and see if the election counter is increased.