Thanks jgoguen!
I just updated to 2.6.0 and haven't done any reading/highlighting yet, but I did a quick comparison between the old kepub and the new. Maybe I'm doing something wrong but as far as I can see, they are the same regarding spaces between spans.
Code:
<span class="koboSpan" id="kobo.9.1"> The barrister and the journalist, left thus unceremoniously on a crowded pavement, looked at each other.</span> <span class="koboSpan" id="kobo.9.2">Breton laughed.</span>
I will read and make highlights later and see if there is a difference.
Thanks for the amazingly quick update!