I am sure I am not the only one that is, or in the future will, be developing applications in a mixed-client environment. Today some (most) of our users are on R5, while other are running Notes 7.0.
What I would like to be able to do is to set a database (sorry, "Application") property, called for example "Notes Target Client version". If I set it to "5.0", I will, when I write my scripts, not have access to, or get a warning, if I use functions that does not exist in R5. This way I could use the latest designer, with all the new features, but still produce R5 code.
Personally I think this would be a great feature. To expand on the idea, the setting could also apply to views (If the db is set to R5, and I create a column with "use value as color", I should get a warning, saying "this column will not show up/work in R5, only in 6.0 and higher". Same thing with other design elements.