MTD Client Onboarding: A Checklist for Accountants (2026–27 and 2027–28 Waves)
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The first wave of Making Tax Digital for Income Tax is no longer a future deadline — it’s live, and the early numbers show how many clients are behind. This is a practical MTD client onboarding checklist for getting the rest of your book ready for the April 2027 and April 2028 waves before the same scramble repeats itself.
Disclaimer: This article provides general information only and does not constitute tax advice. Consult a qualified tax adviser or accountant for advice specific to your circumstances.
MTD Client Onboarding: Why the Next 18 Months Matter
HMRC’s own release data from 12 August 2026 is worth sitting with for a moment. Of the 864,000 sole traders and landlords mandated into MTD from April 2026, only 570,000-plus had signed up, and just 436,000 filed their first quarterly update by the 7 August deadline. That leaves roughly 428,000 clients across the industry already late or non-compliant, four months into the first wave.
That gap tracks with what the readiness data already suggested. IPSE and Sage research found around 70% of sole traders weren’t MTD-ready, with only about 1 in 10 already using cloud accounting software. The UK’s Longitudinal Small Business Survey (2024) found 32% of no-employee businesses use any kind of record-keeping software at all, and 54% are still keeping paper records. Whatever readiness gap you’re seeing in your own client book, it’s consistent with the national picture — and the £30,000 and £20,000 waves are next.
Step 1: Segment Your Client Book by Qualifying Income
Pull prior-year Self Assessment returns and sort clients by qualifying income — gross self-employment turnover plus gross property income, combined, using each client’s own share where property is jointly owned. Three buckets fall out of this:
- Already mandated — over £50,000 in 2024–25, in scope from April 2026. If any of these clients aren’t yet signed up and submitting, they need attention now, not a reminder at the next quarter.
- Next wave — over £30,000 in 2025–26, mandated from April 2027. This is where your onboarding effort should concentrate over the next year.
- Future wave — over £20,000 in 2026–27, mandated from April 2028. Lower urgency, but worth flagging now so nobody is surprised later.
Clients who sit close to a threshold either way are worth a proactive conversation regardless of bucket — qualifying income can move a client into scope earlier than they expect, particularly landlords and clients with more than one income source. See our guide to how qualifying income is calculated for the mechanics you’ll want to walk clients through.
Step 2: Contact Your £30k-Wave Clients During 2026
Clients heading into the April 2027 mandation have roughly a year of runway right now — which is exactly the point at which contacting them does the most good. Use 2026 to get their records digital and let them run one or two “practice” quarters before the deadlines are real and points start accruing. Two things worth confirming early with each client: that they’re registered for Self Assessment, and that they’ve filed a return in the last two years, since both are required before HMRC will let them sign up. Our guide to the April 2027 £30,000 threshold has the detail to share directly with clients in this bucket.
Step 3: Standardise a Records Stack Per Client
HMRC’s own guidance is explicit that MTD doesn’t require one all-in-one product. Dedicated record-keeping software — even a spreadsheet, provided it’s linked digitally — can sit alongside separate filing or bridging software, connected by a digital link. That’s a genuinely useful design decision for a practice, because it means you don’t need every client filing through the same software to get consistent records.
What you do want standardised is the records layer. A practice where every client brings their own system — one on paper, one in a spreadsheet with their own category names, one texting you photos — multiplies the number of formats your team has to interpret every quarter. Picking one records tool to recommend across your book (Taxr among the options) means every client’s export lands in the same shape, with the same categories, regardless of which filing software they eventually submit through.
Step 4: Use the First-Year Waiver to Fix Habits, Not Delay Them
Clients mandated from April 2026 get a genuine concession worth explaining clearly: no penalty points for late quarterly updates in 2026–27. It’s worth being precise with clients about what this does and doesn’t cover — late tax returns and late payments are still penalised in the first year, so it isn’t a blanket grace period. Interest also continues to accrue on anything paid late, on top of any penalty.
The useful way to frame this to clients is as a practice year, not a delay. The quarterly habit still needs to be built now, because points start counting in earnest from 2027–28. Worth also flagging in onboarding: nil updates are mandatory even in a quarter with no income or expenses — a detail that trips up clients (and sometimes internal teams) who assume nothing to report means nothing to submit.
Step 5: Keep the Penalty Mechanics Simple for Client Conversations
You don’t need to walk every client through the full penalty framework, but it helps to have the basics ready: one point per missed deadline (a quarterly update or the tax return), capped at one point per deadline even if a client runs multiple businesses. Reaching 4 points triggers a £200 penalty, and a further £200 applies for each additional miss while at the threshold. Points expire after 24 months if a client stays below the threshold. For the full breakdown to use in client materials, see MTD penalty points explained.
Where the Taxr Accountant Portal Fits
If you’re standardising a records stack across your book, Taxr’s accountant portal at portal.taxr.io is free to use and built for exactly this: a live view of client receipts as they’re scanned, without waiting for a client to remember to send an export. Clients capture receipts through the Taxr app throughout the quarter, and you get organised, categorised records ready to pull into your filing software or hand to whoever prepares the return. It’s a records-layer tool, not filing software — the quarterly submission and final declaration still go through your MTD-recognised software of choice.
See our guide to how accountants use Taxr for a fuller walkthrough, or visit Taxr for accountants to see what the portal includes.
Get Ahead of the Next Wave
The £50,000 wave has already shown what happens when onboarding starts after the deadline rather than before it. With the £30,000 and £20,000 waves still ahead, the practices that segment their book now, start conversations early, and standardise records across clients will spend a lot less time chasing missing quarters later. Download Taxr free — 10 scans on us — or point your clients to it directly as the records-layer habit MTD assumes.