If I upgrade the angular version of my project to the latest one, do I need to upgrade my ag-grid version also to the latest one to make it work? Or, my ag-grid will work without any change?
Generally, an old version will work without change. I'm currently using version 20.2.0 with Angular 8 (the current ag-grid version is 23.1.0).
I'm not sure what will happen if you try to use an older version with Angular 9, using the Ivy Renderer. I expect that it will work ok, but I haven't tried it yet.