Redmine

I’m attaching a patch to make Ruby 4.0 available in Redmine.

• Since ostruct is no longer a default gem, I added it to the Gemfile. https://www.ruby-lang.org/en/news/2025/12/25/ruby-4-0-0-released/#stdlib-updates
• I confirmed that the Ruby 4.0 compatible test suite passes on GitHub Actions. (CI run on my fork: https://github.com/ishikawa999/redmine/actions/runs/21240857495)
• I tried running Redmine on Ruby 4.0 and did a quick check.

Setting the target version to 7.0.0.

Committed the patch in r24367. Thank you.

Marius BĂLTEANU wrote in #note-6:

I'm wondering if it's safe to merge this into 6.1.2 considering there are no breaking changes added by this update? Or how we can ship this faster without releasing 7.0.0 that needs more time to finish the work.

I agree that it is safe to merge this into the 6.0-stable branch.

Traditionally, Redmine has supported newer Ruby versions only with major releases. However, in cases like this—where the new Ruby version requires no code changes or only minimal ones—I think it is reasonable to support it in a minor release.

Setting the target version to 6.1.2.

After upgrading Ruby to 4.0.1 in the Redmine instance in our company, we observed a significant slowdown in CommonMark Markdown rendering. The root cause is still unknown, but our current investigation strongly suggests that the upgrade from Ruby 3.4 to 4.0.1 is responsible.

Therefore, I believe that changes for Ruby 4.0 support should not be merged into the 6.1-stable branch at least until this issue is resolved.