In the same way that it already does with iPhones and MacBooks (Air / Pro), Apple also Watches with ?inflated / inflated? batteries well after the end of the original one-year warranty.
According to 9to5Mac, internal Apple documents already indicated that, in these cases, first generation Watches (aka ?Series 0?) would already be served even one year after the end of the original one-year warranty. That period has now been extended to another two years.
In other words, to make it easier: owners of first generation Apple Watches have nothing to worry about in terms of ?inflated / inflated? batteries (which often cause the screen to ?pop out?, as shown in the photo above) even up to three years after the original purchase date. Apple also often reimburses consumers who may have previously paid for the service, so if so, it's worth contacting the company.
The document to which the 9to5Mac had access specifically speaking of the first generation Apple Watch, but there is no reason to imagine that this same policy would also not be applied to the Series 1 and 2 models. They should not have been mentioned yet, because they were released a few months ago (in September 2016).