HMRC issues new update on 'mandatory' rule changes with November 2026 deadline

MoneyHMRCIt said the second phase window was now open11:39, 18 Aug 2026HMRC has given an update on mandatory changes "designed to raise standards".‌The tax authority said on Tuesday that registration was now open for tax advisers in the second phase of the new Modernising and Mandating Tax Adviser Registration (MMTAR) rollout. It said this applied to any advisers with Self Assessment or Corporation Tax accounts, but without an agent services account (ASA). They have until November 18, 2026, to register, it added.‌HMRC said it was encouraging advisers in the second registration window to check if they need to register and submit their application as soon as possible. It added that more than 4,000 applications were submitted and more than 2,000 accounts created during the first registration