(Re)-installation of packages when changing Julia versions?

If we install the 1.6 development version and later want to upgrade to the upcoming final 1.6 version…
Will we need to reinstall all packages again?

No, not unless you delete your ~/.julia folder - all the packages/binaries are stored there (by default).

1 Like

No, you don’t even need to reinstall packages going from 1.5 to 1.6.


And can I have both executable versions, 1.5 and 1.6, simultanously and single shared folder for the packages? Or do I need to have the packages for v1.5 and also separately the packages for v1.6?

the v1.5 v1.6 folders only tracks what pkg you have(Project.toml, Manifest.toml). They don’t contain actual blob of the packages. Thus, if you have the same version of the same pkg in both 1.5 and 1.6, you will only need 1 copy of the source code of that package, which lives in ~/.julia/packages


Even better: get used to use local projects and keep the very minimum in the global environment, so changing Julia versions doesn’t affect you at all (almost)


I thought it needed to compile the packages for both Julia versions.

that is correct, which is why there are multiple (Julia) version directories under .julia/compiled. But usually precompile is not considered part of the “installation”.

Then the more julia versions I have installed the more space I will spend with the packages too ?

1 Like

You will spend a bit more space with the compiled files but they are quite small.