add added in 1.37 comment

Author: memsharded

mastering/policies.rst

@@ -21,7 +21,7 @@ With the ``build_policy`` attribute in the `conanfile.py` the package creator ca
 - ``missing``: If no binary package is found, Conan will build it without the need to invoke Conan install with :command:`--build missing`
   option.
 - ``always``: The package will be built always, **retrieving each time the source code** executing the "source" method.
-- ``never``: (experimental) Never builds this package from source, this package can only be created with a ``conan export-pkg`` command.
+- ``never``: (experimental, available from Conan 1.37) Never builds this package from source, this package can only be created with a ``conan export-pkg`` command.
 
 
 .. code-block:: python

reference/commands/creator/export-pkg.rst

@@ -139,7 +139,7 @@ There are different scenarios where this command could look like useful:
 
 Packages created with ``conan export-pkg`` cannot be rebuilt from sources in the cache with the ``--build``
 command line argument. It is possible to specify the class attribute ``build_policy="never"`` in this recipes
-(this is an experimental feature) to avoid the ``--build=*`` or ``--build`` argument to try to rebuild them from sources
+(this is an experimental feature, available from Conan 1.37) to avoid the ``--build=*`` or ``--build`` argument to try to rebuild them from sources
 as part of a dependency graph.