That detail surfaced in court proceedings today, as the seized evidence was laid out, and attorney Micheal Avenatti kept a running count. Some of the seized phones were modern cellphones, while others were Blackberries. Although Blackberry phones are still sold, almost no one buys them, suggesting that [Trump's attorney Michael]Cohen has been keeping his old phones long after he’s upgraded to new ones. This means the Feds now have electronic records of his phone calls, voicemails, emails, and other cellular communications dating back many, many years. It also appears to mean that Cohen was using multiple current phones.-Robert Wenzel
Even if Cohen upgraded to a new phone every other year dating back to the Blackberry era, that still wouldn’t add up to sixteen phones. So it’s reasonable to conclude that he’s been running around with multiple phones that are currently in service.