I have some old vector illustrations I did years ago with Adobe Illustrator that don't render properly in Inkscape due to the handling of Illustrator mesh gradients. I'm just wondering whether there is any ongoing work on this, or whether I should open up Illustrator on a Windows machine and convert them to EPS or something? I'd love to be able to use Inkscape to export these files in different sizes and / or edit in the future, but they just don't look right at the moment.

Most of us here are end users. I didn't see anything specific in the release notes, so I suggest asking the developers in the chat : https://chat.inkscape.org/channel/inkscape_user (separate login)

EPS would also flatten the gradient (convert the gradient to objects) IIRC? By the way an Illustrator import project is ongoing, but I don't think mesh gradient support is the focus for now. You can try it out yourself here: https://gitlab.com/inkscape/extras/extension-ai