If it is an LTE version it will receive the update much later unfortunately. Reason why I will not buy an LTE watch from Samsung again that will be more pricy but receive updates ages and ages and ages later for almost no apparent reason.
Just reassure you. I have a watch 6 classic LTE in the UK. I'm still waiting for mine. The update will arrive soon. You just have to be patient. It'll be worth the wait.
The One UI6 update for watch 6 classic has started to roll out this week. As updates are released in batches, it may take days or even weeks to reach your device.
Note that some users are already reporting issues with their watches after updating so you may wish to read up on this before updating.....
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