I could support name=yes and alike but I can't drop the \setupletter[list=...] because you need it to define your own reference line with personalized elements, e.g. your working in a company a put a sign for the letter there plus the number of the office etc.
I'm sorry, didn't think of that. It makes sense, of course.
Another possibility would be removing the "backaddress=yes" switch completely. Then if backaddress data is supplied it's printed along with the line below and if not, well, then leave out the separator line.
What do you think?
Have you tried what will happen with a enabled backaddress and no value for backaddress, fromname and fromaddress are shown as backaddress but I don't rely on this feature and change it to waht you suggested.
I've just tried this quickly and this seems even better … then what about removing the option "backaddress=yes" from "\setupletterstyle" and provide a key "auto" for "backaddress" in "\setupletter"? Thus: 1. No backaddress line \setupletter [fromname={Arthur Thor}, fromaddress={Hidden Street 2\\57895 Mysterytown}] 2. backaddress line generated from sender information \setupletter [fromname={Arthur Thor}, fromaddress={Hidden Street 2\\57895 Mysterytown}, backaddress=auto] 3. Custom backaddress \setupletter [fromname={Arthur Thor}, fromaddress={Hidden Street 2\\57895 Mysterytown}, backaddress={Thor Inc., Mystery Street 5, 59875 Hidden Town}] Oliver