mixpanel/mixpanel-php — pull request #12 by podolinek (2014-01-20 16:17:22+00:00)
Title: Posted data with api_key

Endpoint /import for create events older than 5 days require api_key at the end of posted base64 encoded data. More info about this function is on: https://mixpanel.com/docs/api-documentation/importing-events-older-than-31-days (url is wrong with 31 days).