Using visual studio 2013 I have written an outlook addin for office 2013 and this all works fine, however I now need to make it compatible for office 2010.
I thought I would create another project under the same solution which uses the office 2010 addin which all worked fine until I closed the solution and re-opened it and now it is saying it needs migrating.
If I migrate it, it changes the references to use office15 (instead of office14) so it is now essentially a copy of my original project.
Does anyone know how I can sort it to have the addin work for both office 2010 and 2013?
UPDATE: Even when I create a new solution in VS2013 for an office 2010 addin, close and re-open the solution it is still asking me to migrate and then it converts to office 2013.
The add-in should work in earlier Office versions if you don't use new features (new properties and methods). But in most cases, you need to replace the interop assembly with the one which corresponds to Outlook. VSTO allows to run add-ins in different versions of Office. See Running Solutions in Different Versions of Microsoft Office