API Behavior Changes in v5.9.5

This page lists every deliberate change in v5.9.5 that an existing integration can observe, so you can check your code against it before upgrading.

This page is maintained through the release cycle

Entries are added as fixes merge and the list is finalized at release. If you are reading it mid-cycle, treat it as current-but-growing rather than frozen.

No behavior changes have been recorded yet for v5.9.5. If that is still true when the release ships, this release changes no API behavior and you can upgrade without auditing your integration.

Looking for the previous release? See API Behavior Changes in v5.9.4, which turned an invalid subscribers.get search field from a masked empty success into an explicit error.

One general note on error codes

ErrorCode and ErrorText are arrays, not scalars, on most endpoints. A rejection typically returns "ErrorCode": [13], not "ErrorCode": 13. Code written as if (response.ErrorCode === 13) will not match, so use response.ErrorCode.includes(13) or your language's equivalent.

subscribers.get is the exception: it returns a scalar ErrorCode (for example "ErrorCode": 4), consistent with its existing codes 1, 2 and 3. Match it as a scalar.