According to the small business VAT regulation in Austria entrepreneurs whose turnover doesn’t exceed EUR 30.000 (net) in one assessment period are exempted from VAT. If this threshold is exceeded once in five years by not more than 15 % it doesn’t affect the exemption.
They can declare in written form until the enforceability of the decision of the relevant year to waive the exemption. This waiver is binding for at least five years. On January 1st 2017 two amendments of the small business regulation came into effect.
More details in this article by our Austrian TRA Member Roland Manfreda: