Salesforce API version retirement: find old integrations

What retired versions return

• REST: 410 GONE
• SOAP: 500 UNSUPPORTED_API_VERSION
• Bulk: 400 InvalidVersion

Apex classes, Visualforce pages and Flow API versions are not affected; this is about clients calling Salesforce's APIs. Typical culprits are old Data Loader installs, Outbound Messaging set up before 2014, AJAX Toolkit pages and older third-party connectors.

What retires next

Salesforce supports each version for at least three years and gives at least a year's notice before support ends. The SOAP login() retirement can be tested early from Release Updates; the replacement is an External Client App with an OAuth flow. Dates are on the Salesforce deadlines calendar.

Find the callers

1. Setup, Event Monitoring, Event Log Browser. API Total Usage files cover the last 24 hours (30 days with Event Monitoring).
2. Or query the log files and download them:

SELECT Id, LogFile, EventType, CreatedDate
FROM EventLogFile
WHERE EventType = 'ApiTotalUsage'

Each row has API_VERSION, CLIENT_NAME, CONNECTED_APP_NAME, USER_NAME and STATUS_CODE. Filter for versions 40.0 and below. Reading the logs needs the View Event Log Files and API Enabled permissions.

Also check Setup, Bulk Data Load Jobs (the API Version field) and Login History (API Type SOAP Enterprise or SOAP Partner, with its API Version column).

Fix it

1. Raise the version in the client's endpoint (/services/data/vXX.X/).
2. Upgrade Data Loader and connectors; ask vendors for their supported version.
3. Update AJAX Toolkit paths and recreate very old Outbound Messages.
4. Move SOAP login() integrations to an External Client App before Summer '27.

Common mistakes

1. Checking the log once. The free log holds a day, so weekly and monthly jobs are missed unless it is captured every day.
2. Assuming Apex class versions are in scope. They are not.
3. Treating 31.0 to 40.0 as safe because the last retirement passed.
4. Missing the SOAP login() retirement, which hits recent versions too.