https://www.theverge.com/2018/1/4/16849376/white-house-west-wing-ban-personal-devices

Personal devices are now banned from Donald Trump’s White House, according to a statement from press secretary Sarah Sanders. Staff will be still be allowed to use government-issued devices, but they can’t send texts on those devices.

In a statement, Sanders attributes the ban to upholding "the security and integrity of the technology systems.” The move comes only a day after excerpts of journalist Michael Wolff’s new book Fire and Fury: Inside the Trump White House were released, a book that has chagrined the president. Wolff’s reporting was done through multiple staff interviews that Steve Bannon arranged, Sanders told reporters yesterday.