Six years ago an Excel add in was developed using VSTO 3.0 and excel 2007, thank you Microsoft for giving out such a stable platform for developing solutions for Microsoft Office applications.
Add in worked well with Excel 2007 and 2010, Excel 2013 started giving problems as Microsoft decided not to support MDI in 2013, so we had to compile and make few changes to make it work well with the new SDI of Excel 2013. But the code in version control system is from 6 years and wont compile, so we had to create a new project in Visual Studio 2012 and VSTO 4.0 and add all the files to that. New project is compile and was able to get a working add in.
Old add in was published to a shared location(in production) and the update interval is set for a week. We wanted to push the new add in and overwrite the existing one but as the old one has a published location that is in production we could take the risk of publishing the new one to the old published location and test it out there to see if it is properly overwriting the old one.
So we went into the registry and changed the url path of the old one to a new path that has the new add in. When we clicked on the vsto from the new location we were able to overwrite the add in that was installed, but there were multiple entries in the Add/Remove Programs/ Programs and Features for our add ins.
To fake the new add in as old one we gave it the same name(product name) and same guid in the assembly information of the project.
We have decided to try out the new add in, so we published it to the old prod location and the was prompted for something about updating the key.
When clicked on the new vsto old one was overwritten properly and there were no multiple entries in Add/Remove Programs/ Programs and Features for our addin.
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