Why are we being asked to migrate API's from 1.0 to 2.0

A client of mine received an email from Zoho them to migrate their API's from 1.0 to 2.0 for ZohoCRM. The thing is they do not have any custom API's. They do not integrate ZohoCRM with any other services or their website. They use ZohoCRM standalone. They never had to make any custom API's when they originally set it up. What exactly is Zoho asking them. Does this migration only apply to those customers of ZohoCRM that link it to other platforms and services or are all ZohoCRM customers required to do this? Seems odd that a hosted service requires their customers to do any backend maintenance. Below is the email they were sent.

Thanks in advance,
Adam

Hello,

It appears that you are still using Zoho CRM API v1.0. As we announced in a recent forum post, API v1.0 will be deprecated on December 31, 2018. After the deprecation date, API support and enhancements, as well as bug fixes for v1.0 will not be taken up by Zoho CRM.

However, API v1.0 in your existing code will continue to work until the API v1.0 Sunset Date - Dec 31, 2019. All API methods and code written based on v1.0 will become non-operational after the sunset date.

We strongly recommend that you migrate your existing API v1.0 code base to API v2.0 as soon as possible.

API v2.0 offers several major advantages and enhancements over API v1.0, such as :

Increase in the daily limits of API calls (up to 1,000,000 calls)
Multi DC support
Adherence to REST standards
Easy JSON parsing
New API dashboard for better usage analytics
Introduction of API names
Introduction to Connections and Functions
Support for Mobile SDKs, JavaScript SDKs, and Server side SDKs.

For more information, please refer our deprecation of API v1.0 announcement and the migration document from API v1.0 to API v2.0.

If you are not familiar with these terminologies, or if you are unsure of the migration process, please contact the developer who helped you set up this system.