Plugin not loading in older document despite correct installation of present version

Hi, just wondering if there is a workaround for plugins that fail to load on opening an existing document. I suspect I have updated my Waves install since the previous time of accessing the Sonar Platinum document and am having issues with the GTR Toolkit Stereo plugin, inserted within the document, linking with the presently installed (and working) version. Clearly this is problematic as I've lost access to the settings I had configured. Any advice would be most welcome.
 
Only though I had was that it was VST2 when inserted and update is VST3.
 
Thanks, Andrew