X0306 4 2018-02-26 0001170534 MITEL NETWORKS CORP MITL 0001273417 WILLIAMS DAVID M 350 LEGGET DRIVE OTTAWA, ON K2K 2W7 A6 1 Common Shares 2018-02-26 4 M 0 14500 0 A 234500 D Common Shares 2018-02-27 4 S 0 6870 8.3952 D 227630 D Common Shares 2300 I June William (Spouse) Restricted Stock Units 2018-02-26 4 M 0 14500 0 D Common Shares 14500 0 D Represents the automatic withholding of Common Shares to satisfy tax withholding obligations in connection with the vesting of RSUs 2,300 Common Shares were purchased March 3, 2017 by Mr. William's wife, June Williams. Mr. Williams disclaims beneficial ownership of the Common Shares held by his wife and this report shall not be deemed an admission that Mr. Williams is a beneficial owner of such for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or for any other purpose. Represents 14,500 Common Shares underlying 14,500 Restricted Stock Units ("RSUs") granted to Mr. Williams on May 10, 2017. These RSUs will vest on December 31, 2017. /s/ David M. Williams 2018-02-28