✔ 最佳答案
They'll keep a stock of refurbished models to cover warranty claims for unrepairable phones; the last thing they want is to encourage fraudulent claims in order to get free upgrades.
At their option they might exchange a broken and unrepairable 4s for a basic refurbished 5 or 5c when they have no more 4s models in stock, but most policies include a clause allowing insurers to simply pay a fair settlement sum instead.