yes, with this code the skin would just be restricted to version 8.5 as specified in the "msgversions" tag
in order to add compatibilty for version 9 you'd need to change it to
code:
<MsgVersions>
<Version Major="9" Minor="0"/>
</MsgVersions>
string and picture ids, as well as style sheets, etc would all be different with version 9.....but you can extract the resources (via the skinning page of plus preferences) and work through to find what you need