It seems the Android version of DC strips blank lines from incoming e-mails from users who are /not/ using DC. I would argue it is preferable /not/ to alter the message at all such as deleting blank lines. Those blank lines were likely added by the sender to increase readability or for other reasons so DC should not remove them.
We must distinguish between blank lines at start/end of a message, and blank lines between paragraphs. Which do you mean?
I should have been clearer - I was referring to blank lines between paragraphs. I have no problem with empty lines at the start or at the end of a message being removed since that does not alter the presentation of the message.
It was an issue in the past:
From my experience, empty lines in between are not stripped.