In its continued desire to take advantage of modern technology and provide a secure environment for Zoho users and their data, Zoho is upgrading the APIs for many of their applications. The new APIs introduce new features and capabilities but also include the removal or deprecation of some items you may have utilized in the past. The focus of this article is the deprecation of Authtokens and the move to OAuthtokens, or OAuth for short.
Generally, OAuth works very much like the previous Authtokens, but with better security measures built in. You need these to provide access for one application to interact with another. Where you would have had to utilize your password to configure an Authtoken in the past, OAuth allows you to provide those interactive capabilities more securely.
Any custom functions or integrations you're utilizing that rely on Authtokens to communicate with Zoho applications' APIs must be updated to utilize OAuth. Some Zoho applications have already deprecated Authtokens (i.e. CRM, Desk, Creator) while others are still in the process (i.e. Cliq, Books, Subscriptions, Inventory). Additionally, Zoho has provided a FAQs document which can serve as a guide for you to make the transition from Authtokens to OAuth. That is available for download here.
If you require any technical support or for more details about the deprecation of any specific Zoho application, please check with the support resources for that application or contact us.