Jim is correct that it's nothing like a software update, just a small database containing the board ID's of all known iDevices that are allowed to connect. There are no changes to settings or restart required. The last time I checked there were only three small databases that were swapped out for new ones. Similar to XProtect updates, but you get to decide when to do it.
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I never ever had the experience of having Photos open when I connected my iPhone, so I can't relate at all to the previous behavior you described.
Al Varnell