I want to open old designs and replace the old template with newer company template. Is this possible without damaging the file and internal page links?
How old are those files?
Have you just tried it yet?
As long as you’re working on a copy of your files you can experiment all you want without risk of loosing anything.
I do not know how to look into the file to determine the version of KiCad that was used to create the project. Yeah, I agree, nothing to loose trying, I just don’t even know how to try it )
If you open a KiCad file (project, schematic or PCB) in a text editor you’re likely to see a date or some reference to a KiCad version.
Just make a copy of your project, and open it like any normal KiCad project.
KiCad should always be able to open projects made with older versions.
How to change the “template” depends on how you defined it. Assuming you made it by use of the Pl-editor then there should exist a wks file for it. To change it for an existing project open it and then use the dialog found in file->page setup (or similar name – i only have nightly at hand so i can not check how it was called in stable). At the bottom of this dialog you can select the layout description file. (works similarly also for the layout)
The main issue I would expect is if the project was made in for example version 4, and you now open it in version 5. In that case you would be asked to remap the symbols. For details about this process, look at Converting KiCad version 4 projects to version 5 (Remap a project)
If the project was made in an even older version, then there might be other issues as well. But I personally have no experience, as I started using KiCad after version 4 was released.
Excellence assistance … thank you kindly … got it working now. Made another $ to Kicad today, love this platform )