An unopened can of sauerkraut should last up to 5 years and possibly longer.
The canned sauerkraut may not be as fresh after 5 years but it's likely still safe to eat but the good bacteria goes away and it's not as healthy as it was before.
But the canned sauerkraut as long as it's unopened will last several years but once you open the can of sauerkraut you should refrigerate it.
And the opened can of sauerkraut should remain good in the refrigerator for 3 to 5 days before it goes bad.
You can keep many canned goods for years before it goes bad as the canning process preserves the food including the sauerkraut so it extends it's shelf life.
I've had unopened cans of sauerkraut in my pantry for 10 years before and it was still safe to eat but just not as fresh.