18 Contract liabilities

The carrying amount of current and non-current contract liabilities increased year-on-year from EUR 2.0 billion to EUR 2.2 billion. These mainly comprise deferred revenues. The increase resulted from higher contract liabilities in the Germany, Europe, Systems Solutions, and United States operating segments. A decrease in carrying amounts in the Group Development operating segment, primarily as a result of the reclassification of T‑Mobile Netherlands’ assets to non-current assets and disposal groups held for sale in connection with the agreed sale, had an offsetting effect. Revenue of EUR 2,573 million (2020: EUR 1,343 million) from contract liabilities that were still outstanding as of December 31, 2020 was realized in the reporting year. Of the total of contract liabilities, EUR 1,668 million (December 31, 2020: EUR 1,625 million) is due within one year.

For further information on the agreed sale of T‑Mobile Netherlands, please refer to the section “Changes in the composition of the Group and other transactions” under “Summary of accounting policies.”