If you are using the classes that BaseProject returns directly within MyProject, you need to stick with the same version (1.0). But if BaseProject only uses those classes internally and does not share with MyProject, you can safely use the new version (2.0).
Best practice: strongly name your assemblies so that the compiler can help you out.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…