Salesforce Winter ’26 Release API Updates: What Developers Need to Know About API Version 65.0

September 5, 2025

Eren Yılmaz

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Salesforce’s Winter ’26 release (API version 65.0) introduces several API-level changes that affect authentication, messaging, testing, and integration patterns across clouds. This article will highlight the key updates that developers and integration architects should plan for in terms of adoption, compatibility, and migration.

Breaking Changes and Deprecations

Messaging API Field Deprecations

In Winter ’26 (API v65.0), Salesforce introduces new event-driven fields for the Messaging "Bring Your Own Channel" (BYOC) framework. Older fields on ConversationChannelDefinition and CustomMsgChannel objects are now deprecated and scheduled for removal in Spring ’26 (API v66.0). Developers who rely on these fields must migrate to the new schema to ensure continuity.

SOAP API Login Retirement

The SOAP API login() call for versions 31.0 through 64.0 is set to retire by Summer ’27. Applications using these versions must transition to External Client Apps for authentication. Early migration is recommended to avoid service disruption.

Use Your Org’s `My Domain Login` URL for API Traffic

API calls must use the org-specific My Domain login URL instead of instance-based endpoints. Enforcement begins in Winter ’26 for sandboxes and extends to all orgs in Spring ’26. Developers should update integrations that rely on hard-coded URLs.

Data Loader Authentication Change

Support for OAuth 2.0 Device Flow in Data Loader is removed as of September 2, 2025. Integrations using this method need to adopt alternative authentication flows supported by Salesforce.

Activity Data Model Migration

Organizations using Einstein Activity Capture will see emails and related activity data migrate into the standard Salesforce Activity data model. The change begins in Winter ’26 and becomes mandatory in Summer ’26. Integrations that consume activity data should verify compatibility with the standard model.

Platform API Highlights

Limits API for External Services

The Limits API now includes resources for monitoring External Services usage, such as active objects, operations, and registrations. This provides greater observability into service consumption and helps maintain governance across integrations.

Unified Test Execution with Tooling API

New REST endpoints in the Tooling API support unified test discovery and execution:

Test Discovery API lists both Apex and Flow tests.

Test Runner API executes them together, with unified reporting.

This enhancement simplifies automated test execution and centralizes reporting for mixed test environments.

Metadata Deployment Updates

DeployResult now reflects two new states: Finalizing Deploy and Finalizing Deploy Failed. Deployments in the finalizing state cannot be canceled, reducing the risk of metadata corruption. Additional size metrics are also provided to assist administrators in evaluating deployment complexity.

Sales Cloud API Highlights

While Winter ’26 does not introduce new Sales Cloud–specific APIs, two platform-level updates directly impact Sales Cloud integrations:

Einstein Activity Capture (EAC) Migration: EAC-captured emails are now stored as standard Activity records (like Task or EmailMessage), making them accessible via standard REST, SOAP, or Bulk APIs. This change enables reporting and retrieval through tools expecting native activities.

My Domain Enforcement: Any hard-coded API endpoints (e.g., legacy Sales Cloud integrations) must switch to the My Domain-based URL to remain functional.

Developers integrating with Sales Cloud data should validate compatibility with these upcoming changes.

Service Cloud API Highlights

Messaging BYOC Schema Changes

As part of the BYOC migration, deprecated Messaging fields are scheduled for removal in Spring ’26. Developers working with Service Cloud Messaging must transition to the new schema before enforcement.

SMS Channel Configuration in Sandboxes

Service Cloud now supports creating and configuring SMS channels within sandbox environments. This allows teams to test API-driven messaging workflows before deploying them to production.

Data Cloud API Highlights

CRM Analytics Dataset Access

Data Cloud can now consume datasets from CRM Analytics. This feature is introduced in beta and expands the scope of queryable and segmentable data available through Data Cloud APIs.

Activation-Triggered Flow (Pilot)

Developers can activate Data Cloud segments directly to external systems through API-based destinations using Flow. This pilot feature enables pushing segments into external platforms programmatically.

Industry-Specific Data Cloud Integrations

Referral Marketing and Loyalty Management now integrate with Data Cloud segments. Loyalty Management also leverages the Query API and Data Graphs to discover and activate segments across multiple data spaces.

Marketing Cloud API Highlights

Marketing Intelligence Connectors

New API connectors are available in Marketing Intelligence, accompanied by improved semantic model exploration and pipeline scheduling. These changes increase flexibility in managing and ingesting data through APIs.

REST API Triggers for Flows

Marketing automation flows can now be triggered with REST APIs, enabling on-demand execution. Flows can also be tailored with Data Spaces and supported by templates to maintain data consistency across processes.

Mobile and Messaging Enhancements

Developers can configure mobile apps in Setup and send push notifications (basic and carousel) programmatically. Metrics are available for monitoring engagement. A Marketing Cloud Next sandbox is also introduced to support safe API testing.

Web Tracking Connector Updates

Salesforce advises updating external tracking kits and website connectors. API consumers must redeploy data streams and replace tracking scripts to align with the updated connector functionality.

Scoring and Insights Models

Multiple scoring models, including channel-specific models, are supported. While primarily analytics-facing, these enhancements affect data available through reporting and insights APIs.

Industry Cloud API Highlights

OmniStudio introduces enhanced guardrails, including permission-aware ApexClassCheck and new limits on Data Mapper operations. These updates improve performance and security for API-driven orchestrations in industry solutions.

Final Thoughts

The Winter ’26 release (API v65.0) advances API governance, authentication modernization, and cross-cloud integrations. Developers should prepare for deprecated Messaging fields, update hard-coded API endpoints to My Domain, and begin planning for the SOAP API login retirement.

At the same time, new testing, deployment, and Data Cloud features expand the toolkit for building scalable, observable, and API-driven solutions.

For full details, consult the official Winter ’26 Release Notes (API v65.0) on Salesforce Help or check out useful breakdowns released by Salesforce Ben.

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