For Gist to be able to distinguish new users from old ones, it is important to know when your existing users signed up.
Gist tracks signup dates and times in the form of a Unix timestamp. Every modern programming language has ways to calculate these timestamps. Gist only accepts the timestamp in seconds and not in milliseconds. Gist will also acceptISO 8601timestamps if generating a Unix one is not possible or is troublesome.
What if I don't know or can't generate the timestamp?
If you are unable to generate the timestamp, then your signup date will be incorrect for all users, and as such some features like “Message users who signed up in the past 7 days" will not work correctly.
This would lead to issues with segmenting users because signup date is one of the most important user properties that you will need to filter.
Reach out to us if you need any assistance with sending dates in the Unix timestamp form.