The standard deadlines are fixed
The standard quarterly deadline pattern is 7 August, 7 November, 7 February, and 7 May.
Guide
MTD quarterly update deadlines explained
Use this page to understand the deadlines in plain English before you rely on software or a planner to manage them.
There are standard and calendar update periods
Users need to understand which period style they are working with, because the quarter-end dates are not identical.
The first year has a softer quarterly penalty position
That does not remove the need to understand the process, but it does reduce panic around the first-year learning curve.
The year-end stage still matters
Quarterly updates do not replace the need to complete the year-end return/finalisation process.
Practical reminder
The simplest route is usually to understand the reporting rhythm first, then let software support it, instead of depending on software before you understand what the dates mean.
This site is a practical guide and planning resource. It is not official HMRC software and it is not tax advice.