They can change the renewal benefit anytime! Moreover they can change annual fee reversal criteria also anytime. These things are always at bank discretion, but it will be difficult for them to convert a LTF card to paid one unless product itself is discontinued, I did not wanted to move from a LTF card to a paid one. Anyways, my spends on this card is going to remain low(Read-Gyftr Apay voucher). As I said earlier, I just took this card as FOMO effect.