8. Revenue from contracts with customers

Revenue recognized during the period related to the following:

Revenue by categories are as follows:

Other revenue mainly consists of revenue from the sale of production residues in metal production.

Revenue in 2023 includes income of EUR 1,982 thousand (2022: EUR 1,323 thousand) from the reversal of reimbursement liabilities recognized in the previous period. The reversals represent the difference between the recognized expected volume discounts and annual bonuses for customers in the previous period and the actual payment in the fiscal year as well as the differences from recognized deferred revenues from price negotiations with customers of NORMA Group that were not concluded in the previous year.

An analysis of sales by region, can be found at NOTE 30. SEGMENT REPORTING.

Contract assets and liabilities

Contract assets represent revenues from development services rendered, which were realized based on the ratio of costs already incurred to the estimated total costs. The contract liabilities represent advance payments received for goods to be supplied by NORMA Group. Of the contract assets and liabilities, EUR 7 thousand and EUR 1,052 thousand (2022: EUR 450 thousand and EUR 1,295 thousand respectively) are expected to be realized or fulfilled within the next twelve months. The contract liabilities from advance payments received of EUR 1,295 thousand recognized as of January 1, 2023, were recognized as revenue in the fiscal year, net of any sales taxes.