This post is *applicable* only for users who use *Outlook Plugin* and have built applications or integrations using REST API and use Authtoken for authentication and authorization in their REST API client. This is *not applicable* for users using Active Sync/ CALDAV clients for accessing their accounts. 

At Zoho, we have been supporting Authtoken based connections for REST API and our Outlook Plugin uses Authtokens for authentication. When using the Authtoken, the client application uses the username and password to generate an authtoken which the application passes with every request. This mode of authentication, makes it easier for hackers and attackers with the advanced tools and hacking methods to gain access to the user accounts and thereby misuse the account or involve in data theft. Hence we are deprecating support for Authtoken soon, to ensure that your data is secure and accessed via standard . 

Feel free to write to our support team at support (at) zohomail (dot) com in case you need further assistance in this regard.