2026/27 is the first year that quarterly update submissions must be cumulative. This means that the period always starts at the beginning of the tax year (usually 6th April but may also be April 1st). The end date can be today’s date or the date of the most recent transaction that was used to calculate the totals.
HMRC require you to submit cumulative period updates for each of the 4 quarters of the tax year (the quarters usually commence for 6th April but the quarters can also commence from 1st April). You can submit more often than this but be sure to submit after each quarter ends and before its due date about 1 month tater. The Ftax Quarterly update form will guide you.
Click here to view an MTD for IT timeline which shows the periods when the quarterly period updates must be made.
Click here to read how HMRC describe MTD for IT quarterly updates.