The Ubuntu devs are considering upgrading the GTK+ packages to the latest 3.14 version, which was made available just a couple of months ago, a decision that would really help a number of other Ubuntu flavors as well.

GTK+ is a very sensible piece of software that has a lot of stuff depending on it. The Ubuntu devs used GTK+ 3.12 for the previous release and now they intend to upgrade this package, although there are still some issues that need to be solved. The good thing is that we're smack in the middle of the development cycle and there is no better opportunity to make this move.

Developers from other projects have started to ask themselves if Ubuntu plans to switch to the new GTK+, and it seems that this is their plan, if nothing terrible happens or if they don't encounter some bug that would complicate matters needlessly. They also say that they intend to upgrade some of the GNOME apps that are still used by Unity, although they haven't gone into much details about that.

New GTK+ version and updated GNOME packages will make Ubuntu 15.10 quite interesting

The updates for this packages will most likely open up the system for some interesting improvements, but users should not get their hopes up in seeing something very different in Ubuntu 15.10. Canonical always bets on consistency and they're not going to break that, especially now that they are moving to upgrade to Unity 8, and that should be a very important change.

"We do plan to update GTK yes, we have an updated package in the desktop team ppa under testing, but we noticed quite a few regressions & theming issues with the update and we want to get the most important ones resolved before upload. We also plan to update GNOME applications when possible (we mostly need to patch the UI to not use headerbars on Unity, which we already did for a few)," wrote Canonical's Sebastien Bacher in a mailing list message.

The latest GTK also saw the introduction of Mir support, which is actually a big step forward, for both the Ubuntu and GTK+ teams. It will take a while until we get to see how this support actually translates into the project.

In the meantime, if you want to give Ubuntu 15.04 a try, you are free to do so, although for now it's still using the old GTK. That might change pretty soon, so stay tuned.