# Package extensions for Julia \< 1.9

**URL:** <https://discourse.julialang.org/t/package-extensions-for-julia-1-9/93397>\
**Category:** General Usage\
**Tags:** pkg, package-extensions\
**Created:** [January 23, 2023, 12:14pm UTC](https://discourse.julialang.org/t/package-extensions-for-julia-1-9/93397 "2023-01-23T12:14:24Z")\
**Posts on this page:** 4\
**Page:** 2

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**Author:** ![Eben60](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/eben60/32/13475_2.png) [@Eben60](https://discourse.julialang.org/u/Eben60)\
**Post date:** [June 17, 2023, 2:59pm UTC](https://discourse.julialang.org/t/package-extensions-for-julia-1-9/93397/21 "2023-06-17T14:59:07Z")

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If I have `[weakdeps]` and `[extensions]` sections in my `Project.toml`, what happens if I load my package under an older Julia? The implicit answer from what I read is that just would be ignored and cause no errors, but could somebody tell me explicitly?

My possible use case: The main functionality of the package could stay LTS compatible and needs just minimal dependencies, but there would be some special subpackage, using a lot of dependencies, to be run under Julia \>= 1.9

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**Author:** ![jishnub](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jishnub/32/33620_2.png) [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Post date:** [June 17, 2023, 3:44pm UTC](https://discourse.julialang.org/t/package-extensions-for-julia-1-9/93397/22 "2023-06-17T15:44:51Z")

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The weak dependencies will be ignored, but you still need to list them in the `[extras]` section, otherwise the compat specification won’t be intelligible to older versions of Julia. Older versions of Julia only look at the `[deps]` section for dependencies

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**Author:** ![jules](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jules](https://discourse.julialang.org/u/jules)\
**Post date:** [June 17, 2023, 5:53pm UTC](https://discourse.julialang.org/t/package-extensions-for-julia-1-9/93397/23 "2023-06-17T17:53:58Z")

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What was the old `[extras]` section used for exactly? I’ve only seen it in use with tests but I wonder why it wouldn’t be called `[test]` or so then

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**Author:** ![kellertuer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kellertuer/32/220707_2.png) [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Post date:** [June 17, 2023, 5:58pm UTC](https://discourse.julialang.org/t/package-extensions-for-julia-1-9/93397/24 "2023-06-17T17:58:00Z")

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It is also used for packages that otherwise are indirectly dependencies (like packages you need in tests), here ones that you would add with `Requires.jl`, which is the fallback of pre-extension-time one should fall back to if on Julia 1.8 or less.

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