# I can't update Flux to the latest version, probably due to a package compat constraint. How do I fix this?

**URL:** <https://discourse.julialang.org/t/i-cant-update-flux-to-the-latest-version-probably-due-to-a-package-compat-constraint-how-do-i-fix-this/68672>\
**Category:** General Usage\
**Created:** [September 24, 2021, 5:02am UTC](https://discourse.julialang.org/t/i-cant-update-flux-to-the-latest-version-probably-due-to-a-package-compat-constraint-how-do-i-fix-this/68672 "2021-09-24T05:02:49Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![DevJac](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@DevJac](https://discourse.julialang.org/u/DevJac)\
**Post date:** [September 24, 2021, 5:02am UTC](https://discourse.julialang.org/t/i-cant-update-flux-to-the-latest-version-probably-due-to-a-package-compat-constraint-how-do-i-fix-this/68672/1 "2021-09-24T05:02:49Z")

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I recently got a NVIDIA GPU and wanted to run some of my old Flux code, but there is a bug with the older version of Flux and I cannot get it to work. Long story short, I need to update to the latest version of Flux. Experiments with the latest Flux and CUDA packages show that this will fix the bug.

I have about 15 dependencies I’ve added to my project, and I don’t know which one is causing Flux to be held back. I suppose it could be multiple packages holding it back even. How can I sort out this compatibility mess?

I’m less interested in my specific case, so I wont link my code. I don’t want to get side tracked on the specifics of my code base. I am more interested in **what general strategies or tools are used by the Julia community to resolve situations like this?**

Any advice is appreciated. Thank you.

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**Author:** ![mauro3](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mauro3/32/292_2.png) [@mauro3](https://discourse.julialang.org/u/mauro3)\
**Post date:** [September 24, 2021, 5:25am UTC](https://discourse.julialang.org/t/i-cant-update-flux-to-the-latest-version-probably-due-to-a-package-compat-constraint-how-do-i-fix-this/68672/2 "2021-09-24T05:25:50Z")

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Presumably you’ve read [3. Managing Packages · Pkg.jl](https://pkgdocs.julialang.org/v1/managing-packages/#conflicts)?

Anyway, you can try to add a package which is held back, in this case flux, at a specific version `add Flux@1.2.3`. Usually that gives an interpretable error message. Alternatively, you can uninstall one of the other packages, do `up` and see wether that upgrades flux.

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**Author:** ![DevJac](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@DevJac](https://discourse.julialang.org/u/DevJac)\
**Post date:** [September 25, 2021, 3:09am UTC](https://discourse.julialang.org/t/i-cant-update-flux-to-the-latest-version-probably-due-to-a-package-compat-constraint-how-do-i-fix-this/68672/3 "2021-09-25T03:09:24Z")

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Thank you, this solution works well. Compatibility issue like this are just plain hard, but I think the existing documentation and tools to fix this are good.