Some T-Mobile customers who installed Apple’s iOS 10 update on their iPhones got hit with the second reported glitch in the new mobile operating system.

After anecdotal reports that some people with an iPhone 6 or SE had trouble connecting to T-Mobile’s network after updating, the carrier sent out a tweet on Thursday evening confirming the problem.

“iPhone 6, 6+ & SE customers – Do not download iOS10. We are getting reports of connectivity issues & Apple is working on a fix,” the carrier said. By late Thursday night, however, Apple had readied a fix. “Good news! iOS 10 fix is ready early,” T-Mobile tweeted at close to midnight. “Go to Settings > General > Software Update (or > About if you already downloaded) and update away!”

The problems followed an earlier issue with the iOS 10 update that crashed some of the iPhones of some of the first people to install it on Tuesday. Apple aapl quickly fixed the software and told customers whose phones had crashed to connect to iTunes to restore their devices.

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Still, the hiccups have been nothing compared to Samsung’s exploding battery problem in its new Galaxy Note 7 phone. After dozens of customers suffered from exploding batteries, Samsung recalled the device. On Thursday, the Consumer Product Safety Commission followed up with an official recall.

T-Mobile tmus didn’t say how many of its iPhone customers had installed the update in the three days the software has been available. About 20% of iPhone users overall have upgraded, according to a report from Mixpanel.

The iOS 10 upgrade will come pre-installed on the new iPhone 7 line, which reaches customers’ hands on Friday. T-Mobile has said that pre-orders for the latest iPhone set a record and were almost four times the level of the iPhone 6 in 2014, the previous high for the carrier.

(Update: This story was updated at 7:15 a.m. on September 16 to include news that a fix was available from Apple.)