Include minimum version required for commands / options in documentation ("available since")
A common problem when writing cmake scripts is the question of version compatibility of commands and options. It's very hard to determine which version of cmake first supported a particular feature.
Historically there was an attempt to provide Version Compatibility Matrices but they weren't updated for cmake 3.x (see comment at https://cmake.org/pipermail/cmake/2015-March/059982.html for the reasons)
The only current workaround I know of is to either compare different versions of the documentation or search directly in the source repository (obviously both not exactly convenient)
I therefore suggest to add this information to the documentation (e.g. add a small note to each function and option stating ("available since ${CMAKE_VERSION}").