WASHINGTON (Reuters) - The U.S. House of Representatives voted unanimously on Wednesday to require law enforcement authorities to get a search warrant before asking technology companies to hand over old emails.

A lock icon, signifying an encrypted Internet connection, is seen on an Internet Explorer browser in a photo illustration in Paris April 15, 2014. REUTERS/Mal Langsdon

The bill’s prospects in the Senate remain unclear, though the 419-0 vote in the House was likely to put pressure on the upper chamber to approve it.

Under the Email Privacy Act, which updates a decades-old law, authorities would have to get a warrant to access emails or other digital communications more than 180 days old. At present, agencies such as the U.S. Justice Department and the Securities and Exchange Commission only need a subpoena to seek such data from a service provider.

Supporters of the legislation say it is needed to update the 1986 Electronic Communications Privacy Act (ECPA). Technology companies and privacy advocates say that statute was written before the rise of the Internet and so is outdated.

The issue of law enforcement access to private electronic communications has been at the center of an international debate.

This was reflected in the Justice Department’s high-profile pursuit of a court order earlier this year to force Apple Inc AAPL.O to help unlock an encrypted iPhone linked to one of the San Bernardino, California, shooters.

Separately, Microsoft Corp MSFT.O earlier this month filed lawsuit in federal court against the Justice Department, alleging the government is using ECPA in a way that violates the U.S. Constitution.

The company argued ECPA is too often used to prevent the company from notifying its users, sometimes indefinitely, when investigators pry into emails and other data stored on remote servers.

More than a quarter of senators have endorsed similar legislation in the upper chamber to the House bill, including No. 2 Republican John Cornyn.

But it was unclear if Senate Judiciary Committee Chairman Chuck Grassley, who holds jurisdiction over the legislation, intends to move it forward during an election year.

The Iowa Republican will review the House bill, consult with stakeholders and his committee “and decide where to go from there,” a spokeswoman told Reuters in an email.

Senators Patrick Leahy and Mike Lee, the Democratic and Republican authors of the Senate bill, praised the House vote in a statement as “an historic step toward updating our privacy laws for the digital age” and urged quick consideration.