Hey @MattCole - nice to see you in the community.

Thanks for laying out a good detailed explanation of what you’re trying to do, it makes it much easier to help.  :)  

I think there’s a clever way to do this using a “Date Property-Triggered” Flow.  If you’re not familiar, a Flow triggered by the Date Property is an automation you can setup provided you have some properly formatted Date in the users’ profile that you can use to trigger the Flow.  Typically, people use this for Birthday Flows or Purchase Anniversary, where a subscriber gets an email on their Birthday or on the first year anniversary their first purchase.  So the trick here, is how you can add the proper “Date” from a purchase of a 30-Day challenge?

First, I would create each month’s 30 Day Challenge Products distinct from each other within Shopify - either with a “SKU” or a “Variant” or the product Title (e.g. November 30 Day Challenge). This keeps things clean and separated from one month to another, and might be nice if someone wanted to buy the December 30 Day Challenge (even though November is the next one coming up). 

Next, create or use a “Post Purchase Flow” (Triggered on a Placed Order or Fulfilled Order Trigger) that you may already have, and add the Update Profile Property” Action in that Flow so you can add a Date to the customers’ profile property for the First Date of the corresponding 30 Day Challenge (e..g November 1, 2021).  It might look something like this:

Finally, create your 30 Day Challenge Flow that’s Date Triggered. You can follow the step-by-step in Klaviyo’s documentation here:

• Guide to Creating a Date Property-Triggered Flow

This lets you create a Flow for each 30 Day Challenge completely automated. 

Now, that’s only half your question.  The other part is how do we get the Order Email and Order ID in each of these messages to link to their respective PDF files.  Unfortunately, as of now, the Date Triggered Flow is triggered on the Date and has no context of the Placed Order event (which has the Order ID), or which Placed Order event (if someone bought more than once) - but it does have the users’ email address.  I’m not familiar with that digital delivery app (SkyPilot), but could you pass the email address to that link where they can see all their Orders and pick the appropriate order to get their Files? 

Otherwise, there is a second way to do all of the above, but requires developer support or to use a intermediary tool like Zapier to fire those Events into Klaviyo.  You would add Customer Properties via the Klaviyo API and sets Custom Properties with at least these two properties:

• next_order-id: Order ID
• next_start-date: Start Date of Challenge

Once you have this, you can reference these Custom Properties in your email no different than using any Custom Properties (like First Name, etc) since each Profile will store the most recent Order ID and Start Date within the profile.

Since this requires some custom implementation, there’s lots of ways to go about it depending on the approach.  But you can look at this documentation or pass it to a developer to help:

• API Track & Identify

Finally, I should note, you can also manually update all your profiles (the night before the first challenge) with their “next_order-id” by importing the Customer List into Klaviyo with the respective Order IDs that you can pull from Shopify customer export.  It’s a bit more manual which I suspect is what you’re trying to avoid, but at least you only have to do it once a month versus every day.  But here’s how to update Profiles in bulk (manually):

• How to Import Profile Properties Using a CSV Upload

Hope this helps!