What is the difference between the next bill date and at term renewal date?

The next bill date is the subscription’s billing frequency that is specified at the plan level (monthly, every three months, annual) so that is when the change that is made will take effect.  A renewal is the resetting of the term of the subscription, which also corresponds to a billing event. When your customer signs up they agree to a term length which we share more about in our documentation here and when that term ends then, the change that is applied will take effect. For example, if you upgrade an annual plan and apply the change for when the term renews, the plan will be upgraded at the end of the year.