As the audit is carried out as part of your income tax return, the deadlines for submitting the income tax return apply. In principle, the income tax return for a given year must be submitted to the tax office by July 31 of the following year. If there is no obligation to submit an income tax return, you can submit a tax return voluntarily (application assessment). You have four years to do this. You can submit the voluntary tax return for 2023 until 31.12.2027.
Applications for a tax allowance or a higher allowance than ELStAM for the current year must be submitted by November 30 at the latest. After this date, an application for a tax reduction can only be taken into account in an income tax assessment.