Hi there. 
We have our own Outlook Addin which is compatible with all versions of Odoo and Outlook 2013 to 365.
OUS Outlook Odoo Add-In (openusersystems.com)
Feel free to reach out for a chat. 

Hello, you are probably right for outlook after 2013 version, but for outllok 2013 we can't add an URL address.

Only a ....dll file (oàr an executable file)  is possible when you go to : Outlook - File-options-Add Ins !

Are you sure it's possible to update between odoo and OUtlook  2013 ?

Thanks.

Open your Outlook mailbox and select any email.
Click on the More actions button and select Get Add-ins.
Select the My add-ins tab.
Under Custom add-ins, click on + Add a custom add-in, and then on Add from URL…
Read the warning and click on Install.

Hope You Find This Useful,
Peter