Today American Express sent out an e-mail indicating that the American Express Hilton Aspire earns 7x on Gas & Supermarkets. Currently the card earns 7x points on dining & travel. It looks like this e-mail probably contains the wrong information though as when you look at the fine print it still mentions the dining & travel categories rather than gas & supermarkets. There are two possible scenarios:
American Express plans to update the 7x categories to gas & supermarkets
Whoever was in charge of sending the e-mail wrongly selected gas & supermarkets as the 7x categories
Personally my guess is that this was a marketing mistake but you never know, maybe this change is coming soon.
Hat tip to /r/amex