I have done quite a bit of looking on the Redmine website, and executed a number of Google searches, but I have not been able to find an answer to the difference between Redmine 2.x and Redmine 3.x
I imagine that, much like Redmine 1 vs Redmine 2, it has to do with the version of Rails that the platform is built on, but I would be interested to know a little more in-depth about the differences and compatibility.
I imagine, also, that plugins are not compatible between the two versions, so this leaves one to wonder, what are the benefits of using one over the other?
Edit: I do see the Rails version difference listed on the Installation page. What is the difference beyond that?
We using Redmine at work, with version 2.3.3 And now we wanted to upgrade to new versions (security updates). We asked the same question.
And what I founded:
from their news page
This new version brings several improvements to the search engine (it's now much faster and includes new search options) and many new features: default issue status per tracker, multiple emails per user, ability to edit attachment descriptions and more
from their Changelog
...
Feature #13849: Grouped filters in the filter drop-down
Feature #13051: Support any macro in (pdf) export for wiki's and issues
Feature #12097: Multi Thread Support
Feature #8818: Repository user-mapping with multiple email addresses
Feature #11702: Add user/group to multiple projects at once
Feature #4244: Multiple email addresses for each user
Feature #1326: Add / edit an attachment description after upload
...
and more