# Major upgrade question



## Alt (Aug 30, 2009)

Hi, i have a system on 7.1-release and im waiting for 8.0.
So i have questions: 
1. Will software compiled on old system(7.1) work on 8? (i guess yes)
2. This software will run in 'native' mode or some kind of 'emulation'? (i saw options like COMPAT_FREEBSD6 etc). Especially i want to know is there a some kind of speed loss?
3. I have build a custom kernel and world on my 7.1 - how i can be able to use freebsd-update now? It is safe?


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## Beastie (Aug 30, 2009)

1. No, since they use different versions of libraries, unless of course you install the compat7x port, when it's ready.
2. Nothing is emulated. compat7x is just a compatibility layer that provides "links" to the old libraries.
3. It's explained in the freebsd-update chapter of the handbook.

EDIT: It seems compat7x is already there.


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