MS Outlook Calendar Addin

Back in the day working with MS Office 2013, I came across a program to add MS Outlook calendar appointments, event, to the right hand To-do pane.

Since migrating my information from old laptop to the new the software has vanished; whether it was me or the techo we cannot agree on. I can remember it was a ZIP or RAR file and named something like outlook2013addin.

Can anyone help as it is an important piece of software. I believe MS has stated it is no longer supported.