generated: '2026-08-13'
method: searched
source: >-
  https://www.campaignmonitor.com/api/ (version notice and TLS deprecation
  statement), https://www.campaignmonitor.com/api/v3-3/whats-new/ (the 3.2 ->
  3.3 breaking-change list), https://www.campaignmonitor.com/api/v3-2/ (the
  retained previous-version documentation), https://status.campaignmonitor.com/
  (probed 2026-08-13, HTTP 200 — it is the shared "Marigold status page").
description: >-
  Versioning, deprecation and availability posture for the Campaign Monitor API.
  The honest summary: versions are path-based and previous-version docs stay up,
  but there is no dated deprecation policy, no Sunset/Deprecation headers, no
  published sunset date for v3.2, and no public numeric SLA.
versioning:
  scheme: URI path segment
  mechanism: /api/v{major}.{minor}/ in the request path
  current: v3.3
  previous: v3.2
  example: https://api.createsend.com/api/v3.3/clients.json
  docs: https://www.campaignmonitor.com/api/
  notes: >-
    Minor version bumps carry breaking changes — the 3.2 -> 3.3 move paginated
    "Get sent campaigns" (capped at 1000 entries per call) and changed several
    response payloads. Campaign Monitor labels these explicitly as "breaking
    changes" on the What's New page.
deprecation:
  policy_url: null
  policy_published: false
  changelog: https://www.campaignmonitor.com/api/v3-3/whats-new/
  sunset_header: false
  deprecation_header: false
  rfc8594: false
  notes: >-
    No deprecation policy document, no notice period, and no RFC 8594
    Sunset/Deprecation response headers. Previous-version documentation remains
    published at /api/v3-2/ and the v3.2 routes continue to answer, but no
    end-of-life date has been announced for them. The API does carry one
    in-band deprecation signal: error code 110, "Deprecated Method", returned
    when updating client details the old way.
  deprecated_items:
    - item: Legacy TLS 1.0 and 1.1 transport
      status: removed
      replacement: TLS 1.2
      evidence: >-
        "We have deprecated support for the legacy TLS connections v1.0 & v1.1.
        TLS v1.2 is our current supported protocol at this time."
        (https://www.campaignmonitor.com/api/)
    - item: Updating client details via the legacy method
      status: deprecated
      code: 110
      evidence: >-
        Error 110 "Deprecated Method" on the Clients API
        (https://www.campaignmonitor.com/api/v3-3/clients/)
    - item: API v3.2
      status: superseded
      replacement: v3.3
      sunset_date: null
      evidence: https://www.campaignmonitor.com/api/v3-2/ remains published; no end-of-life date announced.
sla:
  url: null
  public_uptime_target: null
  notes: >-
    No public numeric uptime SLA for the API. Availability commitments, where
    they exist, sit inside enterprise agreements.
status_page:
  url: https://status.campaignmonitor.com/
  http_status: 200
  provider: Marigold (shared status page across the Marigold brand family)
  probed: '2026-08-13'
  notes: >-
    The status page is branded "Marigold status page" rather than Campaign
    Monitor specifically, and it returns 403 to plain automated clients — it
    answered 200 only with a browser User-Agent. There is no documented
    machine-readable status feed (no /api/v2/status.json Statuspage endpoint).
support:
  help_center: https://help.campaignmonitor.com/
  vulnerability_disclosure: security/campaignmonitor-vulnerability-disclosure.yml
  trust_center: https://trust.campaignmonitor.meetmarigold.com/
ownership:
  parent: Marigold
  note: >-
    Campaign Monitor is a Marigold brand ("Campaign Monitor by Marigold"). The
    trust center and status page are Marigold-hosted, which is why they sit on
    meetmarigold.com rather than campaignmonitor.com.