Julia 1.10 is now LTS instead of 1.6, consequences for us

[fingolfin]

Julia 1.10 is now the Julia LTS release.

Should we draw consequences from this? Some we might want to consider:

1. we might raise the minimal required version for OSCAR from 1.6 to something higher, possibly even 1.10
   • pro: some features (e.g. package extensions) don't work in 1.6
   • con: excludes users (does the gain justify it?)
   • more pros/cons?
2. we may wish to stop CI testing with 1.6 (even if we don't explicitly drop 1.6 support), as work needed for supporting it will increase over time
   • e.g. we just needed CI: add workaround for new gcc with julia 1.6 on github runners #4189 and a similar change now is required fro all our other packages that run OscarCI on Julia 1.6 as part of their CI tests.
   • to stick with my example from above: package extensions require Julia 1.9 so we could decide to use that as minimal version

To be clear: I am not strongly advocating for this, but the question came up in Slack and I think it would be good to make our plans on this explicit.

(Personally I wonder if it might be a bit soon for requiring 1.10, given that it was released Dec 26, 2023 and so is not even a year old. OTOH if people use juliaup as they IMHO should there isn't much of a reason why they couldn't just update to 1.10... )

[fingolfin]

We discussed this during triage:

• no general objections
• some suggestions to make a last release supporting 1.6 printing a warning that no new updates would be made
• however this then got a lot of concern that people might be happily using an older Julia and OSCAR and don't want to be nagged (so at the very least such a warning should include simple instructions for how to disable it)
• overall no consensus on this idea, but anyway, we don't need this right now (it could always be implemented after the fact as Julia allows us to release updates to 1.1.x and 1.2.x etc. even when e.g. 1.3.0 is already out)

[JohnAAbbott]

As a user, I would appreciate being given some warning of such a change. How much warning? Upgrading from Julia 1.6 ought to be fairly quick and simple (on most platforms). Maybe a good time to make the change would be between semesters (in case OSCAR is being used for some teaching courses)?

[fingolfin]

@JohnAAbbott Implementing such a warning would require a new release that still works on the old Julia, but when loaded in that, prints the warning (e.g. as part of the banner). Certainly doable. It may help some people, it may annoy some others... In practice I expect most users won't even notice it.

On the other hand, the old OSCAR will keep working fine for them. They'll just notice that when they try to update OSCAR, it won't. If they then contact us, we can explain the situation. But again based on experience, many people won't try that step -- I think it would thus be prudent for us to mention the minimal required Julia version prominently in the README, and on the website, with something like this:

The current OSCAR version requires at least Julia 1.XY. If you are stuck on an older version of Julia, you can still use older OSCAR versions. However, we strongly recommend upgrading to at least Julia 1.10, the current long-term support release of Julia.

[JohnAAbbott]

Sorry! I was unclear. By "warning" I meant "forewarning." For instance, on the Installation page on the Oscar website, there could be a short message about old and new versions, and their respective requirements -- including a forewarning that from version 1.2 (?), whose release is planned in 2025Q1 (say), Oscar will require Julia-1.10 (or something along these lines). I hope this is clearer.

[fingolfin]

Julia folks are considering dropping support for Julia before 1.10 in JLLs which would force our hand if done. See JuliaPackaging/Yggdrasil#9788