Apple announced Monday evening it received a declassified National Security Letter from the U.S. government, the first such instance of the typically secret demands sent by law enforcement agencies.

The disclosure of the declassified National Security Letter came as part of Apple’s latest transparency report, which covered requests received between July 1 and Dec. 31. It also included disclosure of 5,750 to 5,999 classified National Security Letters.

Read: FBI Gag Orders: FBI Secret Subpoenas To Collect User Data From Tech Companies Dropped 5 Percent In 2016

The letters typically come from the FBI and are used to demand the phone and email records of an individual user from tech companies. They have also been used to acquire IP addresses associated with the user and other electronic records, including browsing history and web records.

Essentially the only piece of information that cannot be obtained are the contents of direct communications, which require a warrant.

The FBI typically uses the letters to compel or demand technology companies and phone and internet service providers to hand over information from their customers. In many cases, the letters are accompanied by a gag order that prevents the company in question from informing the subject of the letter their information has been accessed by the government.

While the declassified letter received by Apple will likely remain secret, its declassification suggests the case in which the letter was involved may have concluded or moved to a point where strict classification was no longer needed. The declassification also removes the gag order.

Apple isn’t the only company to see a letter declassified. Earlier this year, Microsoft revealed the first declassified National Security Letter, which it also received in the second half of 2016. In a blog post, the company said there “are times when secrecy is vital to an investigation, but too often secrecy orders are unnecessarily used, or are needlessly indefinite and prevent us from telling customers of intrusions even after investigations are long over.”

Read: Microsoft Releases First National Security Letter It Received From FBI

The declassification is likely the result of the USA Freedom Act, which was passed in 2015 as a reform of the Patriot Act. Under the law, there are periodic reviews of decisions made by the Foreign Intelligence Surveillance Act, including all classified surveillance requests like the National Security Letters received by tech companies. If a review shows that a letter no longer needs to be classified, the review can declassify it.

Recent figures published by the Office of the Director of National Intelligence show that not only are classifications on the letters being overturned but fewer National Security Letters are being sent. In 2016, the FBI sent 12,150 letters, down 5 percent from 12,870 the year prior and significantly down from its peak of 56,507 requests in 2004.

Part of the decrease likely has to do with tech companies increasingly fighting against the orders. Earlier this year, Microsoft won the right to continue a lawsuit against the U.S. Department of Justice on behalf of its customers over ongoing gag orders that effectively prevented the company from ever informing a user of a government investigation.

Adobe also succeeded in a challenge over an indefinite gag order, which a federal judge determined was unnecessary and overreaching.

Twitter has been an outspoken opponent of the secret subpoenas as well, calling them an "Orwellian situation." The social network also won a  suit over a government demand to reveal the identity of an anonymous user who had criticized the president.