# Running Old Project on Latest Julia Version?

**URL:** <https://discourse.julialang.org/t/running-old-project-on-latest-julia-version/114356>\
**Category:** General Usage\
**Created:** [May 16, 2024, 12:48pm UTC](https://discourse.julialang.org/t/running-old-project-on-latest-julia-version/114356 "2024-05-16T12:48:41Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**Author:** ![Palli](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/palli/32/3380_2.png) [@Palli](https://discourse.julialang.org/u/Palli)\
**Post date:** [May 16, 2024, 5:19pm UTC](https://discourse.julialang.org/t/running-old-project-on-latest-julia-version/114356/8 "2024-05-16T17:19:11Z")

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Julia has a syntax guarantee, since 1.0/0.7. Julia also has a stable API guarantee, but some _undocumented_ “API” is used by some packages, and then Julia potentially changes, and they break. Either you don’t update Julia, or you do, and then upgrading packages usually fixes. This is probably less of a problem over time, and you can try updating up one Julia version at a time, at least if you have a problem, or I guess just jump to latest, at least try it first.

There has been no new, or at least changed _syntax_ since 0.7. [Except if I recall in 1.7, something new and _technically_ breaking, not in practice, very obscure related to nD matrix syntax.]

I wasn’t aware of that warning but here’s the solution (or one of):

> [@The active manifest file is an older format](https://discourse.julialang.org/t/the-active-manifest-file-is-an-older-format/72963/2):
>
> From the release notes: A new Manifest.toml format is now used that captures extensible metadata fields, including the julia version that generated the manifest. Old format manifests are still supported and will be maintained in their original format, unless the user runs Pkg.upgrade\_manifest() to upgrade the format of the current environment’s manifest without re-resolving (#40765). Nothing is wrong, you’re just getting a warning so you know there’s been a change of versions. You can run up…

> Nothing is wrong, you’re just getting a warning so you know there’s been a change of versions. You can run `upgrade_manifest` to get rid of the warning.

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