Sprint is upgrading its 'unlimited' plan to keep up with T-Mobile and Verizon - here's what's new

Sprint on Thursday announced that, starting February 17, its unlimited data plan will offer high-definition video streaming and 10 GB of LTE mobile hotspot data a month for new subscribers.

The upgrades come just days after T-Mobile updated its "One" unlimited plan to include the same features, which itself came in response to Verizon's re-entry into the unlimited plan market earlier in the week. AT&T announced it was introducing a new unlimited plan on Thursday as well.

Sprint currently caps all video streams on its unlimited plan at a less-than-HD resolution of 480p by default. Subscribers who want HD video streaming on an unlimited plan have to pay for a separate $75-a-month offering. 

The carrier also limits mobile hotspot usage - which allows a phone to be used as a portable WiFi router - to 5 GB of LTE data a month on the default unlimited plan, and 3 GB of LTE data a month on the $75 plan.

Now, Sprint says new subscribers will be able stream video up to a sharper 1080p resolution on the default plan. Gaming and music streams, which were also throttled under the old plan, will be raised from a slow 2 Mbps to 8 Mbps, and from 500 Kbps to 1.5 Mbps, respectively.

As with before, subscribers that exceed the designated amount of LTE mobile hotspot data in a given month will have that throttled to 2G speeds for the rest of the pay period. Both T-Mobile and Verizon knock subscribers down to faster 3G speeds once they go past that 10GB-a-month allotment.

Notably, Sprint says that the updates only apply to new subscribers and those who purchased five lines of service for $90 a month as part of a price promotion that carrier rolled out earlier this month. Current Sprint unlimited plan subscribers who do not have the five lines for $90 plan will be stuck with the same conditions as before.

That promotion, as a reminder, allows new customers to buy one line on its unlimited plan for $50 a month, and anywhere from two to five lines for $90 a month. Those places will stay in place for new customers here, but they'll still only last until March 31, 2018. At that point, Sprint will raise prices back to their normal rates, where one line costs $60 a month, two lines cost $100 a month, and every line beyond that costs an additional $30 a month.

To get any of these prices, though, you'll have to enroll in auto-pay billing - otherwise, Sprint charges another $5 a month.

That's still less than both T-Mobile One, which starts at $70 a month for one line, and Verizon's unlimited plan, which starts at $80 a month, but it notably doesn't include monthly taxes and fees, which raise the final cost up somewhat. Verizon doesn't include those fees in its advertised rates, either, but T-Mobile does.

As with all of its peers, Sprint's unlimited plan isn't technically "unlimited." The carrier says it may slow certain subscribers' speeds in areas of congestion once they use more than 23 GB of LTE data in a given month. T-Mobile and Verizon give similar warnings - for T-Mobile, it's 28 GB, and for Verizon, it's 22 GB.

The updates bring Sprint closer to parity with Verizon and T-Mobile on a feature-by-feature basis as it offers its plan at a lower price. But its network is still widely seen as lacking compared to its peers. A recent study from mobile research firm OpenSignal, for instance, found it to be firmly in fourth place in terms of overall LTE coverage and speeds.