Offline updates

Hello,

Apologies- I also posted this in the snapcraft forum, but I think it might be more appropriate here.

I’m building an application that will need to be updated offline (no internet access). In fact these devices will be offline their whole life- they are only online at the factory. Field updates are done by an operator with a USB drive and terminal access- no internet is possible. Snaps seem to be ideal for this since their dependencies are packaged in. But I’m curious about snapd and the core snap.

So lets say I ship a device (let’s call it ‘target’), running a snap. Some time goes by, I build a new snap with new features, using a up-to-date version of Ubuntu. But the target device has the same version of snap and snapd that I shipped it with- is this OK? Or will I need to update snap or snapd on the target?

I see that I can do ‘snap download core’ to get the current core snap. Is it enough to do an offline install of the “latest” core snap and then my snap? Or is it possible that installing a new core snap will have other dependencies?

Sorry about all the questions. Thanks in advance.

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Yes, you should just be able to download, transport via usb stick, and then install core snap updates as you outline. You will want to grab the .assert file as well and snap ack that first on the target device.