Verizon Wireless says it has a big announcement coming next week, and rumors suggest the mobile carrier will start offering rollover data and a "safety mode" that lets customers use slower data without paying overage fees once their monthly high-speed data allotments run out.

The new plans are described in the above image, which was posted by a Reddit user and allegedly comes from a Verizon test site that occasionally leaks new offerings before they hit the main Verizon website. Verizon didn't confirm or deny the new offerings, but the company vaguely told news sites that "We're going to have some fireworks next week—stay tuned."

The "Carryover Data" referenced in the Verizon leak would let customers roll unused data over to their next monthly allotment, similar to rollover plans introduced about 18 months ago by T-Mobile USA and AT&T.

Verizon's rumored "Safety Mode" would let customers keep using data at slower speeds after exceeding their monthly limits. Instead of automatically being charged overage fees, they would have the option to either keep using slow speeds for the rest of the month or purchase extra high-speed data. This feature would be included with Verizon's XL (12GB) and XXL (18GB) plans, and it would cost $5 per month to enable on smaller data plans.

This is similar to how T-Mobile lets customers use data at a slow 128kbps when they exceed their high-speed data allotments. Sprint introduced a similar plan last year.

Verizon has previously resisted offering rollover data and other features that might save customers money, with CFO Fran Shammo telling CNET in a January 2015 interview that "it doesn't make financial sense" to hold on to customers who leave Verizon because of its prices, which are generally higher than those of its rivals. But T-Mobile has continued its surge, adding 1 million retail postpaid connections and 807,000 retail prepaid connections in the most recent quarter. In the same time frame, Verizon added 640,000 retail postpaid connections and lost 177,000 prepaid ones, but the company still has 112.6 million retail connections compared to T-Mobile's 51.2 million (excluding wholesale).