The backtrace shows:
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xcf in position 0: invalid continuation byte
You state in your bug report that your locale is set to el_GR.UTF-8; so 'utf-8' codec should be correct and your input should be in utf-8 encoding.
Confusingly, I can't see why your input would *include* the listed 0xcf byte. The UTF-8 encoding of λ is 0xce 0xb4.
If this problem is reproducible, please do:
echo -n <text_to_paste_into_prompt> | od -tx1
Attach the result of this command to this bug.
Then, instead of typing the answer into the do-release-upgrade terminal, please cut and paste the text there and verify that the backtrace is still reproducible.
The backtrace shows: rror: 'utf-8' codec can't decode byte 0xcf in position 0: invalid continuation byte
UnicodeDecodeE
You state in your bug report that your locale is set to el_GR.UTF-8; so 'utf-8' codec should be correct and your input should be in utf-8 encoding.
Confusingly, I can't see why your input would *include* the listed 0xcf byte. The UTF-8 encoding of λ is 0xce 0xb4.
If this problem is reproducible, please do:
echo -n <text_to_ paste_into_ prompt> | od -tx1
Attach the result of this command to this bug.
Then, instead of typing the answer into the do-release-upgrade terminal, please cut and paste the text there and verify that the backtrace is still reproducible.