The high-level shakeups aren't over at BlackBerry just because the company has a new CEO. The company has just let go of Chief Operating Officer Kristian Tear (pictured at left) and Chief Marketing Officer Frank Boulben (right), both of whom had assumed their roles roughly one year ago. There's no mention of immediate replacements. The Waterloo firm is also replacing Chief Financial Officer Brian Bidulka with the company's Compliance head James Yersh; Bidulka will stay on as an advisor for the rest of the fiscal year to ease the transition. CEO John Chen hasn't provided explanations for the individual departures, but he describes the executive shuffle as necessary for focusing on BlackBerry's "core strength" in mobile device management. Let's just hope that Chen is better at engineering a turnaround than his predecessors.