# How to brew install swi-prolog 8.4.3 when 9.0.0 is out

**URL:** <https://swi-prolog.discourse.group/t/how-to-brew-install-swi-prolog-8-4-3-when-9-0-0-is-out/5973>\
**Category:** Installing\
**Created:** [November 27, 2022, 4:58pm UTC](https://swi-prolog.discourse.group/t/how-to-brew-install-swi-prolog-8-4-3-when-9-0-0-is-out/5973 "2022-11-27T16:58:54Z")\
**Posts on this page:** 1\
**Showing post:** 4

<div class="post-metadata">

**Author:** ![AmrSol](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/amrsol/32/4991_2.png) [@AmrSol](https://swi-prolog.discourse.group/u/AmrSol)\
**Post date:** [November 30, 2022, 5:01pm UTC](https://swi-prolog.discourse.group/t/how-to-brew-install-swi-prolog-8-4-3-when-9-0-0-is-out/5973/4 "2022-11-30T17:01:31Z")

</div>

It finally works! The thread suggested by @EricGT was very useful. Here is how:

For some reason downloading [SWI-Prolog](https://www.swi-prolog.org/pldoc/doc_for?object=manual) 8.4.3 from the website is causing me another slew of errors. Therefore I went back to SWI-Prolog 9.x via homebrew.

By implementing D.Cox’s pyswip [PR #133](https://github.com/yuce/pyswip/pull/133/files), I get the “Exception: [swi-prolog](https://www.swi-prolog.org/pldoc/doc_for?object=manual) version number could not be determined”.

Then I implemented @hakank 's [suggestion](https://swi-prolog.discourse.group/t/best-easiest-way-to-downgrade-to-version-8-4-3-on-linux-ubuntu-20-04/5966) by amending Cox’s “PL\_version = \_lib.PL\_version” to “PL\_version = \_lib.PL\_version\_info”

Viola! Thankfully, it works! In case anyone is curious, I have been using Aleph.

---

_[View the full topic](https://swi-prolog.discourse.group/t/how-to-brew-install-swi-prolog-8-4-3-when-9-0-0-is-out/5973)._