I see no option in the document or properties function of the printer options. Usually I do! I am new to Libre. Thank You
I have printed duplex in other applications for years?
I offer you a screenshot of another Brother printer dialogue, under Linux, which may help.
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Did you check if your printer supports the function “Duplex”?
Did you install the correct and current printer driver?
For me it looks like this:
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With me Windows 10 Home; Version 1903; 64-Bit | LibreOffice, Version: 6.2.5.2 (x64).