# Incompabilities between package versions

**URL:** https://discourse.julialang.org/t/incompabilities-between-package-versions/23609
**Category:** New to Julia
**Created:** [April 27, 2019, 10:29pm UTC](https://discourse.julialang.org/t/incompabilities-between-package-versions/23609 "2019-04-27T22:29:43Z")
**Posts on this page:** 1
**Showing post:** 6

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### Author: ![Mattriks](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mattriks/32/351_2.png) [@Mattriks](https://discourse.julialang.org/u/Mattriks)
#### Post date: [May 3, 2019, 5:35am UTC](https://discourse.julialang.org/t/incompabilities-between-package-versions/23609/6 "2019-05-03T05:35:00Z")

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Yes currently installation order matters when their are version dependencies. If you have added a package A independently (the latest version) to an environment, and later try to add package B which depends _on a different version_ of package A, then currently the pkg manager does not auto-regrade package A. Instead the pkg manager throws a warning that the version of A you have already is not compatible with the version of B you’re trying to install.

It’s different when you add package A to an environment with B, because A does not depend on a version of B. So in this case the pkg manager gives you a version of A which is compatible with B’s Project.toml.

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_[View the full topic](https://discourse.julialang.org/t/incompabilities-between-package-versions/23609)._