how can i change the version of my project to an older one?

[Mazyar Moghtader 0]

hi there. how you do?

recently i installed the new version of MI and i accidently opened one of my very important projects with it and i had forgot to backup it first! the new version is very cool and i like it a lot but i cant use it because in my computer its very lagy and annoying and i cant even render a 10 second plan with it because it takes nearly 1 hour for every 10 second of rendering.

i dont know if this problem is going to be solved or not but even if its not for me the earlier version of MI was perfect and all i want is to continue my project in that version but doing this is out of my hands.

is there any way to do that and can someone please help me?