# Recommended way to migrate an existing package to Pkg3

**URL:** <https://discourse.julialang.org/t/recommended-way-to-migrate-an-existing-package-to-pkg3/11560>\
**Category:** General Usage\
**Created:** [June 9, 2018, 7:26pm UTC](https://discourse.julialang.org/t/recommended-way-to-migrate-an-existing-package-to-pkg3/11560 "2018-06-09T19:26:13Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![dfdx](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dfdx/32/120_2.png) [@dfdx](https://discourse.julialang.org/u/dfdx)\
**Post date:** [June 9, 2018, 11:36pm UTC](https://discourse.julialang.org/t/recommended-way-to-migrate-an-existing-package-to-pkg3/11560/3 "2018-06-09T23:36:37Z")

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Thanks for your reply. Unfortunately, your suggestions are relevant only for newly generated or already migrated projects, not the ones that you migrate from Julia 0.6 where there’s just no `Project.toml`.

I’ve found a relevant thread [here](https://discourse.julialang.org/t/problem-with-reassignment-of-uuid-when-a-package-is-registered/11422), especially [this](https://discourse.julialang.org/t/problem-with-reassignment-of-uuid-when-a-package-is-registered/11422/14) and [this](https://discourse.julialang.org/t/problem-with-reassignment-of-uuid-when-a-package-is-registered/11422/15) comments. In particular, they state that one should not create their own `Project.toml` and still add dependencies to REQUIRE for now. But here’s a problem: my package [Espresso.jl](https://github.com/dfdx/Espresso.jl) depends on (now external) `LinearAlgebra` module. I’ve added it to `REQUIRE`, but when testing the package fails with:

> ERROR: The following package names could not be resolved:
> 
> - LinearAlgebra (37e2e46d-f89d-539d-b4ee-838fcccc9c8e in manifest but not in project)  
> Please specify by known `name=uuid`.

If I manually create `Project.toml` and run `add LinearAlgebra`, tests run fine. So either I do something that isn’t recommended at the moment (adding `Project.toml`), or my package gets broken.

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