# Ask Pkg to resolve oldest possible versions for dependencies

**URL:** https://discourse.julialang.org/t/ask-pkg-to-resolve-oldest-possible-versions-for-dependencies/93585
**Category:** Package Management
**Tags:** deprecation, semver
**Created:** [January 26, 2023, 4:26pm UTC](https://discourse.julialang.org/t/ask-pkg-to-resolve-oldest-possible-versions-for-dependencies/93585 "2023-01-26T16:26:47Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![Krastanov](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/krastanov/32/6817_2.png) [@Krastanov](https://discourse.julialang.org/u/Krastanov)
#### Post date: [January 26, 2023, 4:26pm UTC](https://discourse.julialang.org/t/ask-pkg-to-resolve-oldest-possible-versions-for-dependencies/93585/1 "2023-01-26T16:26:48Z")

</div>

The compat for many of my packages looks like `LibraryA = 0.1,0.2,0.3,0.4,0.5,0.6`. I am starting to worry that I have inadvertently started relying on features introduced on a latter version that I simply did not notice are not available in a version from 2 years ago that is still in the compat. Of course, I can start manually checking, but I would much rather have CI check it for me. Thus I need to figure out how to tell `Pkg` to install the oldest permitted versions of dependencies. Any idea how to do that?

I believe I have seen actual runtime failures due to this in the wild, e.g. [Precompilation failure caused by package dependency version](https://discourse.julialang.org/t/precompilation-failure-caused-by-package-dependency-version/92995) , which is what prompted me to worry about this with my packages.