opening older blend files in 2.63 breaks the meshes. Help!

Hello blender community.

I downloaded the latest version of blender 2.63a. I’ve worked on a little project in 2.61. After downloading 2.63a I opened the 2.61 file in the 2.63a version, but the mesh of the model I created was extremely deformed. So My question is, how do I get that blend 2.61 file and keep everything (at least the model) as it was normal in the previous blender versions into the newer 2.63a version.

Thank u

but the mesh of the model I created was extremely deformed.
Maybe it would help if this made any sense. What do you mean by deformed ? Add screenshots and link to your blend file.