As part of this change of Microsoft 365 solutions, we announced on November 27, 2023 that both the SharePoint Add-In extensibility model and the use of Azure ACS for SharePoint Online authentication needs are retired as we believe Microsoft 365 customers will benefit more from modern SharePoint extensibility models and modern authentication offered by Microsoft Entra ID. The retirement of SharePoint Remote Event Receivers is part of these announcements, but we want to address the feedback we've received from our partner ecosystem and offer a better transition path from Remote Event Receivers. If you are deploying a Remote Event Receiver as part of a SharePoint Add-In or if you're using Remote Event Receivers registered using Azure ACS as the authentication system, then these Remote Event Receivers will follow the same retirement timeline as the one communicated for SharePoint Add-Ins and Azure ACS use for SharePoint Online. If you are registering your Remote Event Receivers using an Entra application that uses the sites. Selected role for getting granular access to one or more site collections, then those Remote Event Receivers will continue working until July 1st, 2027. To learn more about this approach you can read the Use remote event receivers without Azure ACS dependency article. Today Remote Event Receivers support a synchronous and asynchronous model, whereas web hooks are designed to be asynchronous. We are not planning to support synchronous web hooks, we recommend partners to redesign business flows that depend on synchronous operations.
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Read more at https://bit.ly/4cnZxkv
Source: Microsoft Tech Community SharePoint Blog
