WASHINGTON — An upgrade to streaming video app Periscope will likely make TV news organizations happy.

Periscope’s update for iOS users lets broadcasters and viewers hold their phones sideways, filling the screen with an image that suits traditional television stations and online news organizations.

Since Periscope’s introduction earlier this year, the app’s natural orientation was Portrait — vertical.

Shortly after launch, Periscope’s CEO and co-founder Kayvon Beykpour said the vertical orientation was chosen because most mobile phone users hold them vertically, yet he said horizontal orientation would at some point become an option.

Periscopers have been able to choose to hold their phones horizontally, which required viewers to turn their phones to have the image fill their small screens.

However, the flow of viewers comments only ran vertically, requiring someone watching a horizontal video to cock their head 90 degrees to read the comments.

Now, the comment flow adjusts, depending on whether the viewer is watching horizontally or vertically.

Users who choose view horizontally-produced video will be able to watch, but the image will not fill the screen.

Television news organizations have struggled to integrate Periscope into their broadcasts, because the narrow vertical orientation doesn’t fill the traditional TV screen.

In the past year, vertical video has become more popular, particularly with people who predominantly view content on mobile phones. Snapchat, for instance, is producing content that is natively vertical.