Hi,
I don't think this is about which OS you are using, that is for sure that if you delete an event, your colleague would be notified.... unless if you are not using notification trick like you can do it in outlook;
Configure your Outlook to “Work Offline” status.
Go to your calendar and select the meeting you want to cancel and double click to open it.
In the popping up Meeting window, click on the “Cancel Meeting” option.
Then click “Send Cancellation” button.
Now the cancellation email will be stuck in the Outbox, because right now you are working on “Work Offline” status, so go on to the Mail box andopen the Outbox folder.
In the Outbox folder, right click on the email and then right click on the invitation notification mail and select Delete option from the right-clicking menu.
Hope that it works for you, that also should sync with your iPhone.
Good luck...