Meta Attribution Window Change 2026: Why Conversions Dropped and What to Fix
What the Meta Attribution Window Change 2026 Actually Removed
On October 16, 2025, Meta published an announcement on its developer blog: beginning January 12, 2026, the action_attribution_windows parameter of the Ads Insights API would stop returning two values - the 7-day view (7d_view) and the 28-day view (28d_view). The change applied to every API version at once and hit eight endpoints spanning the ad account, campaign, ad set, and ad levels.
Read that carefully, because the panic in early 2026 came from misreading it. Meta did not stop counting view-through conversions and did not change how campaigns deliver. The change is a reporting surface change: when you request insights with those attribution windows through the API, those windows no longer come back. If your dashboards, reports, or a connector pulled view-through conversions from the API, your numbers shrank overnight even though the ad delivery system behaved identically.
The same announcement also tightened historical data in breakdowns. Unique-count fields such as unique_actions and hourly breakdowns are limited to 13 months of history; frequency breakdowns to 6 months; marketing-mix-modeling breakdowns moved to asynchronous jobs only. Totals for API fields are unaffected and remain available for up to 37 months.
Which Attribution Windows Survived
The windows that continue to be available through the API match what Ads Manager shows: 1-day click, 7-day click, 28-day click, 1-day engaged view, and 1-day view, plus the default windows derived from your account's attribution settings, for fields like actions, conversions, and results.
The practical consequence: long view-through tails are gone from API reporting, but everything click-based is intact. A conversion that came from a click 6 days ago still shows under 7-day click. A conversion from someone who saw but never clicked your ad used to appear under 7-day or 28-day view - those attributions no longer surface through the API at all. If a meaningful share of your reported conversions sat in view-through windows before January, your API-sourced numbers dropped by exactly that share - which is why many teams reported a 20-40% overnight drop that had nothing to do with campaign performance.
Why Your Tracker and Ads Manager Now Disagree More
If you run traffic through Keitaro, Binom, or another tracker, you already know that tracker numbers and Ads Manager numbers never match perfectly. After January 12, 2026, the gap has a new, permanent component. Your tracker records a conversion when the postback arrives - it does not care whether Meta would attribute that conversion to a click or to a view 20 days ago. Meta's API reporting, meanwhile, no longer returns the view-through windows where many of those conversions used to surface.
Three diagnostic consequences follow. First, a widening tracker-versus-Ads-Manager gap after mid-January is expected and does not by itself indicate a broken integration - compare against click-attributed windows only. Second, if your reports or a client's dashboard showed Meta-sourced view-through conversions, re-baseline the dashboard to click windows or totals, otherwise every week-over-week comparison is broken. Third, the change is API-side: Ads Manager's own reporting columns behave consistently with what the API now returns, so there is no alternative interface where the old windows still live.
The general workflow for reconciling the two systems - from click IDs to attribution settings - is in the Facebook Ads conversion discrepancy guide.
Adapting Your Reporting Stack
The migration is mostly bookkeeping, and it splits into three moves. First, audit every dashboard, report, and connector for 7d_view and 28d_view - including the combined window values some tools request - and switch them to 7-day click or account-default attribution. Requests for the removed windows return empty data, so a silent empty chart is the failure signature, not an error message.
Second, mind the new history limits: unique-count and hourly breakdowns stop at 13 months back, frequency breakdowns at 6 months. If your analytics needs long-horizon unique trends, export and store the history now - the totals remain available for 37 months, but breakdowns do not.
Third, and most durable: keep your own record of conversions. A server-side pipeline that logs every event with its own event_id gives you a numbers source that no platform can re-define - the mechanics are in Meta CAPI event deduplication and event ID deduplication. If you route tracker postbacks into Meta, MOST keeps that pipeline running with retries and deduplication handled, and the manual single-landing path is Pixel Activator.
What Did Not Change
The 2026 change lives entirely in the Ads Insights API. Campaign delivery, auction behavior, and conversion optimization still use Meta's internal attribution, including view-through signal for optimization where applicable. Your Conversions API integration is untouched: events still ingest under the same rules, including the 7-day event_time import limit - a different 7-day constraint that trips people up, covered in why Meta rejects events older than 7 days - and the delay mechanics behind it in Meta CAPI event delay.
One caution before you "fix" numbers that look wrong: do not re-attempt importing old events to compensate for missing view-through reporting. Events beyond the import limit get rejected, and a batch with one stale event fails entirely. The attribution window change and the ingestion limit are unrelated constraints - fixing one by violating the other just trades a reporting gap for error 2804003.
For the full server-side picture around Meta conversion delivery, start at the Meta Conversions API complete guide.