Sprint was planning to shut down its WiMAX network today, but the company was forced to keep parts of it running for an extra 90 days after a judge granted an emergency injunction.

A group of nonprofits sued Sprint over the shutdown, saying that Sprint plans to throttle service after the switch from WiMAX to LTE in violation of a contract. A Massachusetts Superior Court judge yesterday granted an emergency motion for a preliminary injunction, saying that the "plaintiffs have demonstrated a strong likelihood of success on the merits."

Mobile Beacon and Mobile Citizen, which supply schools, libraries, and nonprofits with wireless Internet over the WiMAX network, said that "the emergency relief orders Sprint to maintain the WiMAX network in certain areas for 90 days to allow Mobile Beacon and Mobile Citizen time to migrate their users to Sprint's LTE network."

"We will comply with the court’s decision to delay WiMAX decommissioning where it could affect current Mobile Beacon and Mobile Citizen customers only," a Sprint spokesperson told Ars. This includes states outside Massachusetts even though the ruling came from a state rather than a federal court.

Mobile Citizen and Mobile Beacon say the order affects "more than 300,000 mostly low-income Americans, including 1,820 nonprofits, 429 schools, and 61 libraries across the country." The groups provide $10-per-month, unlimited Internet to the schools, libraries, and nonprofits.

As we wrote previously, Mobile Citizen and Mobile Beacon have licenses to Educational Broadband Service (EBS) spectrum, which they leased to Clearwire for 30 years in exchange for payments and use of the network. Sprint bought Clearwire in 2013 and is shifting WiMAX spectrum to LTE.

Mobile Citizen and Mobile Beacon say that Sprint is required to provide unlimited data, but instead the company plans to throttle customers after they use 6GB in a month, bringing speeds down from 6Mbps to 256kbps.

This is a "near lethal blow to plaintiffs' non-profit users whether they be educational institutions, which educate children in traditional brick and mortar schools, or children who attend cyber schools because they do not have access to brick and mortar schools, or the senior or disabled person whose lifeline to medical care and other benefits is through the Internet," the groups said.

Sprint told Ars that it disagrees with the judge's decision, but it will try to reach an agreement with Mobile Citizen and Mobile Beacon. "We do hope that Mobile Beacon and Mobile Citizen will take this time to work cooperatively with Sprint to resolve the contract dispute," Sprint said. "Our goal is to ensure that our EBS partners and our subscribers can use Sprint’s best 4G LTE advanced broadband services as soon as possible."

While the judge's granting of a preliminary injunction doesn't settle the matter entirely, the order said that while the case is ongoing, plaintiffs must get the same service they would receive under their agreements with Clearwire. Sprint is not required to reactivate any parts of the WiMAX network that had already been shut down or provide service better than what Clearwire was contractually obligated to provide.