What does channel num_updates mean? Some LND wallets provide a channel's "Number of Updates". Here's an example from Zap Desktop:



The LND gRPC API Channel Reference cites a property called num_updates. The description of this field is not very informative:


  The total number of updates conducted within this channel.


What specifically is a channel update?
For some reason stackoverflow has a 50 reputation limit on comments, so I must use the answer box to point out that Karlo's answer is not correct - or at least does not tell the whole story. I understand that this is not the correct use for the answer box, blame stackoverflow's poorly thought out reputation limits.

I have a node with a few (outgoing) channels, have not spent a single satoshi with it yet. So the "remote balance" of the channels has always been 0, in other words there have been no balance updates. Yet the number of updates in the channels is non-zero.