@Farinaz
They decided to discontinue QBD UK version and will not develop a new version. You may have some options as follows:
1. If your company is located in UK, consider migrating to QBO.
https://quickbooks.grsm.io/UK
2. If your company is not located in UK, consider migrating to QBD 2021 US version with the one time license or QBO version with region you are located. You will need a 3rd party conversion service.
https://quickbooks.grsm.io/EU
3. If you are using a one time (outright) license of QBD 2019 UK version, you may keep using it for good. Otherwise, purchase a new one time license of it if required.
