Steve Dowling, Apple’s vice president of communications, said today that he’ll be leaving the company next month. First reported by Recode, Dowling’s departure is the latest in a series of unexpected Apple leadership changes as the company continues to evolve under CEO Tim Cook, and could mark a turning point for the historically secretive company.

In a memo sent to employees, Dowling noted that he will assist in a transition of responsibilities to an interim communications manager, Apple senior VP of marketing Phil Schiller, as the company looks for a replacement. Dowling said that he plans to spend a “good, long stretch of time off” with his wife and children before “trying something new,” but had only positive things to say about his 16 years at Apple, which he called the highlight of his career.

According to the report, Apple plans to consider internal and external candidates for the key communications role, which was previously occupied by Katie Cotton — a shrewd and somewhat feared confidant of late Apple CEO Steve Jobs who left five years ago, as Cook continued to build out his own team. At the time, there were questions over whether the company would change its communications strategy, but to the outside world, Dowling largely followed Cotton’s footsteps, though there has been no shortage of lower-level personnel changes since then.

Apple’s leadership team has seen quite a few changes over the last two years, including the addition of SVP and general counsel Katherine Adams, SVP of machine learning and AI John Giannandrea, and SVP Deirdre O’Brien, as well as the departures of chief design officer Jonathan Ive, retail chief Angela Ahrendts, and now Dowling, to name a few. Disney chief Bob Iger, a prominent member of Apple’s board of directors, abruptly stepped down¬†five days ago due to the potential for conflicts between Apple’s and Disney’s streaming services.

Meanwhile, Apple’s market valuation has plateaued at just over $1 trillion,¬†largely on solid continued sales of iPhones, Apple Watches, and an increasing array of services. But the company has been forced to continually respond to often self-inflicted controversies ranging from hardware recalls to privacy lapses.

After next month, those issues will be Schiller’s to handle until a new communications chief is selected. Based on Apple’s past hiring timelines, it could take until the end of 2019 or early in 2020 for a replacement to be selected: The company took until April 2015 to officially name Dowling as Cotton’s permanent replacement after she left in May 2014, though he was named the team’s interim leader in October 2014.