# How to use Manifests for a clean environment for reproducibility

**URL:** <https://discourse.julialang.org/t/how-to-use-manifests-for-a-clean-environment-for-reproducibility/69755>\
**Category:** General Usage\
**Tags:** reproducibility\
**Created:** [October 14, 2021, 8:01am UTC](https://discourse.julialang.org/t/how-to-use-manifests-for-a-clean-environment-for-reproducibility/69755 "2021-10-14T08:01:11Z")\
**Posts on this page:** 1\
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**Author:** ![sijo](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@sijo](https://discourse.julialang.org/u/sijo)\
**Post date:** [October 14, 2021, 8:45am UTC](https://discourse.julialang.org/t/how-to-use-manifests-for-a-clean-environment-for-reproducibility/69755/3 "2021-10-14T08:45:11Z")

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> [@Things that are easier in Julia than Python/R etc](https://discourse.julialang.org/t/things-that-are-easier-in-julia-than-python-r-etc/69403/50):
>
> I ask because in R and Python, I occasionally discover I’m using old or obsolete packages, update them, and that’s that. In Julia, what happens is as you update one package, a bunch of other packages are downgraded.

I love the standardized package management in Julia and find it rather robust, but I’ve had a similar experience with the version management: packages are often held back to old versions or even downgraded. This seems to happen much more frequently than in other ecosystems and I’d like to know why!

Maybe it’s because Julia’s ecosystem is relatively immature and moving faster. Maybe developers are more casual with making new major (backward incompatible) releases: Suppose A just released version 0.13. You have installed B 1.5 that supports A 0.13. If later you install C that hasn’t been updated and only support A 0.12, it will downgrade both A and B. If A is fast moving, this can happen a lot.

Another possibility is that we see more composition and reuse in Julia’s ecosystem, so packages have more dependencies on other packages by third-party developers, with different release schedules… This composition is great in some ways but also has costs… Maybe together with fast moving packages it can explain some of the difficulties with dependency resolution?

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