generated: '2026-08-13'
method: searched
source: >-
  https://docs.customer.io/integrations/llms.txt (per-SDK changelog and upgrade
  guide index) and the GitHub releases API for the customerio organization
provider: Customer.io
providerId: customer-io
summary:
  api_changelog_published: false
  sdk_changelog_published: true
  scheme: semver (per library)
  note: >-
    Customer.io publishes NO dated changelog for its REST APIs. There is no
    "API changelog", "release notes" or "what's new" page anywhere under
    docs.customer.io/integrations/api/, and the App API, Track API and
    Pipelines API specs all carry info.version 1.0.0 with no date. Every
    changelog Customer.io does publish belongs to a client library. That is the
    finding: the SDK layer is versioned in public and the API layer is not.
api_surface:
  changelog_url: null
  evidence:
  - url: https://docs.customer.io/journeys/changelog/
    http_status: 404
    checked: '2026-08-13'
  - url: https://docs.customer.io/integrations/llms.txt
    http_status: 200
    checked: '2026-08-13'
    finding: >-
      17 changelog pages indexed, every one of them scoped to a mobile or web
      SDK version line. None describes the REST API.
  in_spec_signal: >-
    The only in-band change signal on the API is prose inside operation
    descriptions — the metrics operations label their period + steps query mode
    "Version 1 (Deprecated)".
sdk_changelogs:
- platform: iOS
  url: https://docs.customer.io/integrations/sdk/ios/whats-new/changelog/
  upgrade_guides:
  - https://docs.customer.io/integrations/sdk/ios/whats-new/4.0.0-upgrade/
  - https://docs.customer.io/integrations/sdk/ios/whats-new/3.x-upgrade/
  - https://docs.customer.io/integrations/sdk/ios/whats-new/2.x-upgrade/
- platform: Android
  url: https://docs.customer.io/integrations/sdk/android/whats-new/changelog/
  upgrade_guides:
  - https://docs.customer.io/integrations/sdk/android/whats-new/4.x-upgrade/
  - https://docs.customer.io/integrations/sdk/android/whats-new/3.x-upgrade/
- platform: React Native
  url: https://docs.customer.io/integrations/sdk/react-native/whats-new/changelog/
  upgrade_guides:
  - https://docs.customer.io/integrations/sdk/react-native/whats-new/6.x-upgrade/
  - https://docs.customer.io/integrations/sdk/react-native/whats-new/5.x-upgrade/
- platform: Flutter
  url: https://docs.customer.io/integrations/sdk/flutter/whats-new/changelog/
- platform: Expo
  url: https://docs.customer.io/integrations/sdk/expo/whats-new/changelog/
entries:
- component: iOS SDK
  version: 4.7.3
  date: '2026-08-10'
  breaking: false
  source: https://github.com/customerio/customerio-ios/releases/tag/4.7.3
- component: React Native SDK
  version: 6.6.2
  date: '2026-08-07'
  breaking: false
  source: https://github.com/customerio/customerio-reactnative/releases/tag/6.6.2
- component: Flutter SDK
  version: 4.2.1
  date: '2026-08-07'
  breaking: false
  source: https://github.com/customerio/customerio-flutter/releases/tag/4.2.1
- component: Android SDK
  version: 4.20.1
  date: '2026-08-06'
  breaking: false
  source: https://github.com/customerio/customerio-android/releases/tag/4.20.1
- component: Node SDK
  version: v5.3.0
  date: '2026-07-24'
  breaking: false
  source: https://github.com/customerio/customerio-node/releases/tag/v5.3.0
  note: >-
    Tagged on GitHub but not published to npm — registry.npmjs.org still lists
    5.2.0 (2026-07-15) as latest as of 2026-08-13.
- component: Python SDK
  version: v3.2.0
  date: '2026-07-24'
  breaking: false
  source: https://github.com/customerio/customerio-python/releases/tag/v3.2.0
- component: Ruby SDK
  version: v6.2.0
  date: '2026-07-24'
  breaking: false
  source: https://github.com/customerio/customerio-ruby/releases/tag/v6.2.0
- component: Go SDK
  version: v3.12.0
  date: '2026-07-24'
  breaking: false
  source: https://github.com/customerio/go-customerio/releases/tag/v3.12.0
- component: CLI
  version: v0.0.20
  date: '2026-07-23'
  breaking: false
  source: https://github.com/customerio/cli/releases/tag/v0.0.20
- component: Python SDK
  version: v3.0.0
  date: '2026-05-11'
  breaking: true
  source: https://github.com/customerio/customerio-python/releases/tag/v3.0.0
- component: Ruby SDK
  version: v6.0.0
  date: '2026-05-11'
  breaking: true
  source: https://github.com/customerio/customerio-ruby/releases/tag/v6.0.0
window:
  from: '2026-04-28'
  to: '2026-08-10'
  note: Recent window only; not a complete history.
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com