Every GA4, Ads and consent change — dated, what it breaks, and the fix that's been verified.
Google ships measurement changes faster than any guide can stay true. This log records each one, names what it breaks in a real setup, and hands you the artifact that fixes it — stamped with the date it was last verified. Nothing stale is ever shown as current.
44 changes logged · 17 in 2026 · 9 artifacts current · 2 archived with banners · re-verified quarterly · last check 9 Sept 2026
| What it breaks | Fix artifact | |||||||
|---|---|---|---|---|---|---|---|---|
| 1 Sept 26 | Google Ads | AI Max auto-upgrade of Search campaigns begins (rolls out through 30 September) | high | A September-against-August comparison at account level measures the migration schedule, not the product. Campaigns arriving from broad match land with text customization off; those from automatically created assets land with it on — different doses per cohort. | AI Max migration date fields (GAQL) | has artifact | 2026 | 9 Sept 26 |
| 19 Aug 26 | Google Ads | Google Ads API v25.1 exposes metrics.original_conversion_value | medium | 'Conv. value' and every ROAS built on it carry the value-rule multipliers inside them; finance reads a bidding instruction as revenue. | Conversion value audit checklist | has artifact | 2026 | 9 Sept 26 |
| 11 Aug 26 | GA4 | Custom integer lookback windows for click-through and engaged-view conversions | medium | A property that shortens or lengthens a window changes its key-event counts against its own history and against Google Ads' window; comparisons across the change date read as performance moves. | Attribution reconcile sheet | has artifact | 2026 | 9 Sept 26 |
| 10 Aug 26 | GA4 | Campaign data import validation report | low | Nothing breaks — the join becomes visible. Most 'cost in GA4 is wrong' cases are a source spelled differently in the file than in the landing-page URL, a medium the platform never sent, or a date on the wrong side of a time-zone boundary. | Campaign data import CSV template | has artifact | 2026 | 9 Sept 26 |
| 30 Jul 26 | GA4 | Diagnostic for missing URL parameters affecting campaign data | low | Nothing breaks; the diagnostic names the landing pages whose clicks arrive without the parameters the import joins on. | Source group and UTM audit checklist | has artifact | 2026 | 9 Sept 26 |
| 28 Jul 26 | GA4 | Currency field required when uploading cost data | high | Scheduled cost uploads built before July 2026 fail; dashboards that read imported cost go blank from the failure date. | Campaign data import CSV template | has artifact | 2026 | 9 Sept 26 |
| 9 Jul 26 | GTM | Container behavior for unsupported installation paths (/gtag/js, /gtag/destination) | medium | Containers loaded through a gtag path that relied on the restricted state now run everything; consent-gated custom tags may fire where they did not before. | Screenshot-free GTM checklist | has artifact | 2026 | 9 Sept 26 |
| 22 Jun 26 | GTM | Improved measurement of server-to-server conversions (Floodlight) | low | Floodlight conversion counts step up from the release date without any change on your side; a trend break, not a performance change. | note on the entry | note only | 2026 | 9 Sept 26 |
| 11 Jun 26 | GA4 | Hostname data filter | low | Nothing breaks; a filter applied in testing mode does nothing until activated, and an active filter is not retroactive. | note on the entry | note only | 2026 | 9 Sept 26 |
| 11 Jun 26 | GA4 | New Source Group field; Source Platform updates | medium | Reports and explorations keyed on raw source values split what Source Group now merges; saved comparisons and custom channel groups built on 'facebook' vs 'fb' vs 'instagram' drift. | Source group and UTM audit checklist | has artifact | 2026 | 9 Sept 26 |
| 1 Jun 26 | GTM | Google tag gateway for advertisers via Google Cloud Platform — general availability | info | Nothing breaks; a first-party path changes what ad blockers and ITP see, so collection counts can rise after enabling it — annotate the date. | note on the entry | note only | 2026 | 9 Sept 26 |
| 13 May 26 | GA4 | 'ai-assistant' channel for ChatGPT, Gemini and Claude referrals | medium | Rows move out of Referral (and sometimes Direct) into the new channel from the release date; custom channel groups that already carved out AI referrers double up or conflict. | Source group and UTM audit checklist | has artifact | 2026 | 9 Sept 26 |
| 7 May 26 | GA4 | Data Manager API support for server-to-server events | info | Nothing breaks yet; Measurement Protocol keeps working. New server-side pipelines should be built on the Data Manager API. | note on the entry | note only | 2026 | 9 Sept 26 |
| 1 May 26 | GTM | Improved conversion tracking and attribution for Google Ads-linked properties on server-side Tag Manager | medium | Ads-imported conversion counts from sGTM setups step up from the release date; the GA4-vs-Ads gap narrows without anything changing on your side. | GA4 vs Google Ads gap diagnoser | has artifact | 2026 | 9 Sept 26 |
| 4 Feb 26 | GTM | Google Ads automatically collects a broader range of website event data | medium | Consent gating and Content Security Policies written for the old request set can block or leak the new requests; privacy reviews that inventoried requests are stale. | Consent Mode v2 default snippet | has artifact | 2026 | 9 Sept 26 |
| 16 Jan 26 | GA4 | Conversion attribution analysis report (beta) | info | Nothing breaks; a new place to read assisted credit that will not match the key-events table. | GA4 vs Google Ads gap diagnoser | has artifact | 2026 | 9 Sept 26 |
| 16 Jan 26 | GA4 | Per-conversion attribution settings (beta) for Google Ads customers | high | Two key events on the same property can now use different models; a report that sums them mixes models, and an Ads import from a re-linked property may carry a different default than last quarter. | Attribution reconcile sheet | has artifact | 2026 | 9 Sept 26 |
| 11 Dec 25 | GTM | Built-in Client ID, Session ID and Session Number variables | low | Custom cookie-parsing variables that reverse-engineered the _ga cookies are now the fragile path; they break when the cookie format changes. | Screenshot-free GTM checklist | has artifact | 2025 | 9 Sept 26 |
| 19 Nov 25 | GA4 | Cost data import is now Campaign data import | low | Nothing breaks; every guide, screenshot and internal doc that says 'cost data import' is now wrong by name. | Campaign data import CSV template | has artifact | 2025 | 9 Sept 26 |
| 5 Nov 25 | GA4 | User-provided data attribution improvement | medium | Ads-imported conversions and Customer Match audience sizes step up for properties sending user-provided data; the GA4-vs-Ads gap changes shape. | GA4 vs Google Ads gap diagnoser | has artifact | 2025 | 9 Sept 26 |
| 6 Aug 25 | GA4 | Improved conversion data completeness for properties with two or more linked Google Ads accounts | medium | Key-event counts step up from the release date for affected properties; a trend break that looks like growth. | Attribution reconcile sheet | has artifact | 2025 | 9 Sept 26 |
| 30 Jun 25 | GTM | Google Analytics client no longer serves Google script dependencies on server-side Tag Manager | high | New tagging servers that rely on the GA client to serve gtag.js or gtm.js serve nothing; pages load no tags. | Screenshot-free GTM checklist | has artifact | 2025 | 9 Sept 26 |
| 12 Jun 25 | GA4 | Auto-configured key events for the lead-generation business objective | medium | New key events appear on properties that pick the lead-gen objective; imports into Ads and key-event totals change without anyone marking an event. | note on the entry | note only | 2025 | 9 Sept 26 |
| 6 Jun 25 | GA4 | Consent settings hub enhanced with Tag Diagnostics | low | Nothing breaks; the hub shows which streams send consent signals and which do not. | Consent Mode v2 default snippet | has artifact | 2025 | 9 Sept 26 |
| 8 May 25 | GTM | First-party mode is now Google tag gateway for advertisers | info | Nothing breaks; docs and settings that say 'first-party mode' refer to this. | note on the entry | note only | 2025 | 9 Sept 26 |
| 31 Mar 25 | GA4 | New '(data not available)' value for source and medium | medium | A new row appears in source/medium reports; filters that exclude '(not set)' miss it; Direct shrinks from the release date. | Source group and UTM audit checklist | has artifact | 2025 | 9 Sept 26 |
| 10 Mar 25 | GTM | Containers with Google Ads and Floodlight tags automatically load a Google tag from 10 April 2025 | high | Tag sequencing changes: the Google tag now fires before your consent default if the default is not on the Initialization trigger; conversion counts can step up. | Screenshot-free GTM checklist | has artifact | 2025 | 9 Sept 26 |
| 3 Feb 25 | GA4 | Cost data import required fields reduced to source, medium and date | high | Templates built on the old required set (campaign_id, campaign_name as join keys) still load but join on different keys; rows that joined on campaign now join on source/medium/date. | Campaign data import CSV template | has artifact | 2025 | 9 Sept 26 |
| 13 Jan 25 | GA4 | Consent settings hub in Admin | low | Nothing breaks; the first place to see whether the four signals actually arrive. | Consent Mode v2 default snippet | has artifact | 2025 | 9 Sept 26 |
| 14 Nov 24 | GA4 | Outbound clicks measure only clicks to other websites | low | click events for tel: and mailto: links disappear from the release date; call-tracking dashboards built on Enhanced Measurement break. | note on the entry | note only | 2024 | 9 Sept 26 |
| 13 Nov 24 | GA4 | Config command or Google tag required for custom events | medium | Custom events fired before the Google tag loads stop being processed; a pipeline that sent events without a config silently loses them. | Source group and UTM audit checklist | has artifact | 2024 | 9 Sept 26 |
| 22 Oct 24 | GA4 | BigQuery export adds session-scoped traffic-source fields | medium | Queries that derived session source from the first event of a session disagree with the new fields; two definitions of 'session source' in one warehouse. | GA4 BigQuery: sessions with last-click source and key events | has artifact | 2024 | 9 Sept 26 |
| 28 Aug 24 | GTM | 'Set consent mode override' setting in Google tag settings | low | Nothing breaks; a way to force denied defaults when the code sequencing is wrong. | Consent Mode v2 default snippet | has artifact | 2024 | 9 Sept 26 |
| 28 Aug 24 | Google Ads | New first-party data tools: Tag Diagnostics and consent management | info | Nothing breaks. | note on the entry | note only | 2024 | 9 Sept 26 |
| 19 Jul 24 | GA4 | Session traffic source record in the GA4 BigQuery event export | medium | Hand-built session attribution in BigQuery is now the second-best source; older queries disagree with the interface. | GA4 BigQuery: sessions with last-click source and key events | has artifact | 2024 | 9 Sept 26 |
| 1 Jul 24 | GA4 | Universal Analytics properties stop processing data and are deleted | high | Every UA report, export and migration checklist is dead; anything still pointing at a UA property returns nothing. | UA → GA4 migration checklist | has artifact | 2024 | 9 Sept 26 |
| 27 Jun 24 | GTM | Tag Diagnostics tool | low | Nothing breaks. | Screenshot-free GTM checklist | has artifact | 2024 | 9 Sept 26 |
| 10 Jun 24 | GA4 | Attribution models updated to credit paid search correctly | high | Paid search key events step up and organic search steps down from mid-June 2024; month-on-month channel comparisons across the change read as a shift. | Attribution reconcile sheet | has artifact | 2024 | 9 Sept 26 |
| 22 May 24 | GA4 | Improved attribution channel assignments — fewer key events in Direct | medium | Direct falls and other channels rise from 22 May 2024; a trend break. | Attribution reconcile sheet | has artifact | 2024 | 9 Sept 26 |
| 27 Mar 24 | GA4 | Conversions renamed key events in GA4; 'conversions' now means Ads-imported conversions | medium | Every saved report, API query and doc that says 'conversions' now means something else; two numbers with one word. | GA4 BigQuery: sessions with last-click source and key events | has artifact | 2024 | 9 Sept 26 |
| 6 Mar 24 | GA4 | Universal Analytics 360 advertising features unsupported for EEA traffic from March 2024 | high | EEA audiences and conversion exports from UA 360 stopped filling; anything still expecting them is empty. | Consent Mode v2 default snippet | has artifact | 2024 | 9 Sept 26 |
| 28 Feb 24 | GA4 | Primary Channel Group — the editable default channel for all channel reports | medium | Editing the primary group changes every channel report retroactively for the reporting window; two people editing it break each other's comparisons. | Source group and UTM audit checklist | has artifact | 2024 | 9 Sept 26 |
| 8 Feb 24 | GA4 | Eight platform-agnostic manual traffic source dimensions | low | Nothing breaks; older 'session source / medium' dimensions coexist and can disagree with the manual ones. | Source group and UTM audit checklist | has artifact | 2024 | 9 Sept 26 |
| 18 Jan 24 | Google Ads | Consent mode required for EEA audience and measurement features (the v2 signals) | high | Without the two v2 signals, EEA remarketing lists stop filling and modelled conversions stop; it fails silently. | Consent Mode v2 default snippet | has artifact | 2024 | 9 Sept 26 |
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Every row links Google's own release note or announcement. Severity is our read of what it breaks in a real setup: high = numbers move or data stops; medium = a workflow or a template breaks; low = a comparison or a label shifts; info = worth knowing, nothing breaks. "Verified" is the date we last checked the fix against the sources. Export the visible view as CSV above.
The artifact library
9 things you can paste into your stack — templates, checklists, SQL, sheets, snippets — each stamped verified_on, each re-checked when the log records a change that touches it. Archived ones stay visible with a banner, never as current.
#A-005 · sheet · verified 9 Sept 26Attribution reconcile sheetTwo 28-day exports side by side — last-click and data-driven — per campaign delta, and the Smart Bidding re-baseline arithmetic.#A-003 · template · verified 9 Sept 26Campaign data import CSV templateThe exact columns a GA4 campaign data import (formerly cost data import) joins on today: source, medium, ISO date — with currency on every cost row since 28 July 2026.#A-002 · snippet · verified 9 Sept 26Consent Mode v2 default snippetThe default-denied block with all four signals (ad_storage, ad_user_data, ad_personalization, analytics_storage), placed before the Google tag, plus the update call your CMP should make.#A-004 · sql · verified 9 Sept 26GA4 BigQuery: sessions with last-click source and key eventsOne query over the events_* export: sessions per day, the session's last-click source from the record Google added in July 2024, and key events per session.
One entry: the gap diagnoser
"GA4 says 214, Ads says 391" — the seven causes, ranked, with the expected size of each and the artifact per cause. It lives inside the library now, not as the front door.
Running many properties?
Artifact packs and an agency tier are decided later, by demand. Today every artifact is free; if you want the desk to look at a specific setup, write to team@datameasured.com.