gtm.js snippets to stop honoring gtag('config') commands from October 2, 2026; sites must use gtag.js

Google notified container owners that Google Tag Manager (gtm.js) snippets will no longer recognize or wait for gtag('config') commands; from October 2, 2026 all gtm.js snippets initialize on container load regardless of any config command. Sites that load a GTM snippet but rely on gtag('config') to pass parameters or configure Google Ads or GA4 tags must switch to the gtag.js snippet or use the new gtm init trigger.

Google's help page 'Set up your Google tag installation correctly for gtag.js' explains which installations are supported. The October 2, 2026 date appeared in Google's email to affected container owners; the help page itself says only that the change is coming soon. New deployment snippets no longer include the gtag config command, and the gtm init trigger can be set to wait for a config command to preserve legacy setups.