Javascript SDK UTM persistence behavior change
Incident Report for Mixpanel
Version v2.51.0 of our Javascript SDK included a change to the default behavior of UTM tracking which disabled the persistence of UTM properties as super properties. This resulted in events only having the UTM information tracked on them if that UTM information was present on the URL the event was triggered from unless the initialization option {stop_utm_persistence: false} was set. We've reverted this change so that UTM information is persisted as a super property in v2.52.0 which was released 6/7/2024 12PM PT. We recommend the {stop_utm_persistence: true} initialization option if you use multi-touch attribution models in Mixpanel. Please refer to our attribution documentation ( for how to properly attribute data sent in during this time or reach out to our support team with further questions.
Posted May 28, 2024 - 21:30 PDT