The vintage designation is for products 5-7 years old. Apple does not guarantee part availability in this range but will do repairs if possible. 7+ is consider

The vintage designation is for products 5-7 years old. Apple does not guarantee part availability in this range but will do repairs if possible. 7+ is considered obsolete and they won't touch it. That is old enough that a battery update through a third party or through a DIY vendor like iFixit should be reasonable.