Uwe Stöhr wrote: > I miss a guide of how "old" a feature must be to be added to a layout file > in branch for example.
IIRC we don't have an agreement on this. My personal opinion: A new command/environment which translates 1:1 into a style may be as new as you like (if it is officially released), as long as it is documented that this style may not work with older TeX installations (the latter is needed so that there is at least a chance to look up the reason of the error message you get if you use it nevertheless). For features which do not translate 1:1 into a new style, but are e.g. used in some common preamble code we need to be much more conservative. I would suggest something like "must be available in the current stable TeXLive release and the previous one". And of course there is the question whether such a new feature should be used at all. I remember from the previous discussion on this topic that you used a new command which was 100% equivalent to an older one. In this case, I would keep the old one for a longer time. If others agree on these rules I'll add them to the document. Georg
