# Difference between project.toml and required package versions

**URL:** <https://discourse.julialang.org/t/difference-between-project-toml-and-required-package-versions/112818>\
**Category:** General Usage\
**Created:** [April 11, 2024, 7:12am UTC](https://discourse.julialang.org/t/difference-between-project-toml-and-required-package-versions/112818 "2024-04-11T07:12:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ovanvincq](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ovanvincq/32/31869_2.png) [@ovanvincq](https://discourse.julialang.org/u/ovanvincq)\
**Post date:** [April 11, 2024, 7:12am UTC](https://discourse.julialang.org/t/difference-between-project-toml-and-required-package-versions/112818/1 "2024-04-11T07:12:12Z")

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Can anyone explain to me why the package MMG\_jll.jl cannot be installed with version 7 of SCOTCH\_jll.jl ?

When installing MMG\_jll.jl, Pkg installs the version 6 of SCOTCH\_jll.jl and I cannot upgrade it to version 7 without removing MMG\_jll.jl (my initial problem is that it is not impossible to install simultaneously MUMPS.jl v1.4 and Gmsh.jl v3).

The project.toml file of MMG\_jll.jl is:

```julia
name = "MMG_jll"
uuid = "86086c02-e288-5929-a127-40944b0018b7"
version = "5.6.0+0"

[deps]
JLLWrappers = "692b3bcd-3c85-4b1f-b108-f13ce0eb3210"
Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
SCOTCH_jll = "a8d0f55d-b80e-548d-aff6-1a04c175f0f9"
Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
Artifacts = "56f22d72-fd6d-98f1-02f0-08ddc0907c33"
LinearElasticity_jll = "18c40d15-f7cd-5a6d-bc92-87468d86c5db"

[compat]
JLLWrappers = "1.2.0"
julia = "1.6"

```

The version of SCOTCH\_jll.jl is not specified in the compat section and other packages (LinearElasticity, etc.) do not require SCOTCH\_jll.jl.  
So why is it impossible to install MMG\_jll.jl with SCOTCH\_jll.jl v7?

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<div class="post-metadata">

**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [April 11, 2024, 7:38am UTC](https://discourse.julialang.org/t/difference-between-project-toml-and-required-package-versions/112818/2 "2024-04-11T07:38:46Z")

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You’re looking at the wrong place: what matters is the registry:

> <https://github.com/JuliaRegistries/General/blob/6e2958ed5632ea4c13d978bdb708496b377c2d4c/jll/M/MMG_jll/Compat.toml#L3>

The compat bounds were retroactively added in [Add compat bounds for JLL packages compiled with SCOTCH\_jll by amontoison · Pull Request #81580 · JuliaRegistries/General · GitHub](https://github.com/JuliaRegistries/General/pull/81580)

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<div class="post-metadata">

**Author:** ![ovanvincq](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ovanvincq/32/31869_2.png) [@ovanvincq](https://discourse.julialang.org/u/ovanvincq)\
**Post date:** [April 11, 2024, 8:06am UTC](https://discourse.julialang.org/t/difference-between-project-toml-and-required-package-versions/112818/3 "2024-04-11T08:06:38Z")

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Thanks!

Indeed, I was looking at [https://github.com/JuliaBinaryWrappers/MMG\_jll.jl/blob/main/Project.toml](https://github.com/JuliaBinaryWrappers/MMG_jll.jl/blob/main/Project.toml)

So the modification was made directly on the general registry and not on the package’s github?

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<div class="post-metadata">

**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [April 11, 2024, 11:15am UTC](https://discourse.julialang.org/t/difference-between-project-toml-and-required-package-versions/112818/4 "2024-04-11T11:15:16Z")

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> [@ovanvincq](#):
>
> So the modification was made directly on the general registry and not on the package’s github?

Correct, and that was done to prevent runtime issues (`using MMG_jll` would error because it wouldn’t find libraries it needs, if you used an incompatible version of `SCOTCH_jll`)