New default event properties are now captured with each event, holding campaign data present on the URL at the time of tracking. These include UTM parameters (in the format utm_source, utm_campaign, etc.) and Click Identifiers (e.g., gclid, fbclid, etc.). This functionality can be disabled with the initialization setting {track_marketing: false}.
UTM parameter properties are no longer persisted across pageloads as superproperties. They will be present only on events tracked on the same pageload where they were present initially. (2023-09-13) Correction: UTM parameter properties still persist across pageloads as superproperties. Persistence will be removed in a future release.
For better first-touch attribution, UTM parameters present on the URL on pageload will be "set once" as profile properties (meaning that a new value will not overwrite any existing value on the profile property). These property names take the format initial_utm_source, initial_utm_campaign, etc. This functionality can be disabled with the initialization setting {skip_first_touch_marketing: true}.
Support for automatic page-view tracking has been restored. With the init option {track_pageview: true}, an event named $mp_web_page_view will be tracked on pageload, containing properties identifying the current page (current_page_title, current_url_path, etc.) as well as any UTM parameters and Click Identifiers. Pageview events with these properties can also be triggered manually:
// track a pageview event
mixpanel.track_pageview();
// track pageview with additional properties
mixpanel.track_pageview({'Test variant': 'control'});Automatic page-view tracking may be turned on by default in a future release.
Miscellaneous updates:
- UUID generation now uses
performance.now()when available as part of its time-based entropy algorithm - The network payload format now defaults to JSON for any API host containing the string
mixpanel.com(looser than previous host checks)