Additions and changes to the Twilio platform
Twilio SendGrid started limiting category statistics for all customers on May 16, 2022. Beginning June 22, 2022, Twilio SendGrid will limit all category statistics created before May 16, 2022 on a seven-day rolling basis. This means all categories will be available for the first seven days. After seven days, the top 100 categories will be retained for free customers, and the top 1,000 will be retained for paying customers.
Customers who require access to all category statistics can use the Event Webhook to retrieve and retain the data on their own systems as long as they save it within seven days of first sending the event.
Many customers find that Unique Arguments, which are not limited, are the best solution for their needs. See the "Categories vs Unique Arguments: Benefits & Limitations" blog post to better understand these two tracking tools.