I think their minimum standard is 5 years after they stop selling a product. However, it could go longer if things still work. The 6S was discontinued in 2018,

I think their minimum standard is 5 years after they stop selling a product. However, it could go longer if things still work. The 6S was discontinued in 2018, which would give it support until at least 2023, so we aren’t too far beyond that.