# Downgrade from FreeBSD 12.0



## aragats (Sep 14, 2016)

I was using FreeBSD 11.0-CURRENT for a year - updating it from time to time. Yesterday I decided to update /usr/src and build world. However, I didn't realized that it's going to pull FreeBSD 12.0-CURRENT. Anyway, everything went fine, and I have a working system.

What is the proper way to downgrade it to 11.0-RELEASE?


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## wblock@ (Sep 14, 2016)

Check out the 11-stable source and rebuild.  You'll have to rebuild ports or packages.


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## SirDice (Sep 14, 2016)

To switch the source: `svnlite switch https://svn.freebsd.org/base/stable/11 /usr/src`


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## rferris (Sep 14, 2016)

Definitely a good use case for ZFS boot environments!


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## aragats (Sep 14, 2016)

wblock@ said:


> You'll have to rebuild ports or packages.


I agree in general, but in this case most probably FreeBSD 12 did not moved far from 11, did it?


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## kpa (Sep 14, 2016)

There are some differences now because the code slush (that was in place for splitting stable/11 from head) was lifted a while ago and developers have been free to introduce experimental code in head for more than two months. There is no guarantee that the ABI hasn't changed in that time so you really should reinstall all installed ports when on stable/11.


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## aragats (Sep 14, 2016)

kpa said:


> There are some differences now because the code slush (that was in place for splitting stable/11 from head) was lifted a while ago and developers have been free to introduce experimental code in head for more than two months. There is no guarantee that the ABI hasn't changed in that time so you really should reinstall all installed ports when on stable/11.


Yes, but I've updated my three-month-old 11-CURRENT to 12-CURRENT and now want to go back 11-STABLE.
I don't mind rebuilding ports, just would like to understand the nuances.


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## kpa (Sep 14, 2016)

aragats said:


> Yes, but I've updated my three-month-old 11-CURRENT to 12-CURRENT and now want to go back 11-STABLE.
> I don't mind rebuilding ports, just would like to understand the nuances.



If you didn't rebuild any ports for the updated system that turned out to be 12-CURRENT you can switch to 11-STABLE by the source downgrade method and you don't have to rebuild any ports because the ABI is identical between what was 11-CURRENT and what is now 11-STABLE.


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## wblock@ (Sep 14, 2016)

Yes, I was assuming you had completed the change by rebuilding all ports or reinstalling packages.  If not, you can switch the operating system back.


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