How to upgrade GTK 3.18 to 3.20 on ubuntu 16.04?

Question

While trying to install lollypop I got this error

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/lollypop/container.py", line 79, in update_db
    self.__show_first_run()
  File "/usr/lib/python3/dist-packages/lollypop/container.py", line 335, in __show_first_run
    view = FirstRunView()
  File "/usr/lib/python3/dist-packages/lollypop/view_first_run.py", line 29, in __init__
    builder.add_from_resource("/org/gnome/Lollypop/FirstRunView.ui")
GLib.Error: gtk-builder-error-quark: .:3:50 Required gtk+ version 3.20, current version is 3.18 (7)

Solution

If you Google this, you will find guides like this and this. In addition, you will find that this has been asked before on this very site at least twice: once in 2016 and once in 2015.

Now, to be fair, I'm used to arch, which already ships with 3.20. Being maybe 1 year after the release of 3.20, I almost didn't believe the Ubuntu guides above. Really? Add a separate repository, including one with staging in the name? Nevertheless, it's true and the tl;dr is very simple:

sudo add-apt-repository ppa:gnome3-team/gnome3-staging
sudo add-apt-repository ppa:gnome3-team/gnome3
sudo apt update
sudo apt dist-upgrade

I did these exact steps today, rebooted for good measure, and enjoyed that my preferred openbox themes (which work fine on arch) were no longer messed up (due to 3.18, which I never would have suspected).

Comments

[CynicallyNaive]

Just as a point of information this is the first search result for [upgrade gtk to 3.20], so someone might land on this page after a reasonable effort to Google it. Thanks for the helpful links.

[Dong Nguyen]

It's GNOME3. The question is about GTK3. Are they the same?

[Hendy]

@DongNguyen I think it's just the name of the repository. Take a look at the list of packages in said repository and you'll see an awful lot of 3.20 values for the versions, including gtk+3.0. So yes, I think the answer is accurate: adding this staging repo will updates one's gtk-relevant packages to 3.20.

[Dong Nguyen]

I thing that is for installing the whole Gnome3 DE.

[Hendy]

You're welcome to try it and/or post your own answer. Note that none of the commands above involve install pkgname; so nothing is installed. It simply adds a repo which triggers apt update to see a newer version of relevant packages that are already installed, and it updates them.

[kris]

'google it'? Really? Well I did and it brought me here. I think it's really poor form to answer questions with something that starts with 'google it'. The rest of the answer is good though :-)

[Hendy]

@kris Yeah, really. I only answered this because I'd done it myself based on other guides (that come up with google; just click my link). I think it's bad form to ask answered questions, and StackExchange seems to agree by closing duplicates. In fact, this 2017 question duplicates one from 2016 which duplicates one from 2015. All have the same info.

[kris]

@Hendy sure. I understand. And pointing to places where you found information is very good. Also pointing out that the question has been asked and answered before, those are all good and helpful things to do. I just think you can do all that without saying 'google it'. That just sounds very condescending. And there's really no need for that.

[Hendy]

@kris Fair point. I toned it down just now, linked directly to the previous versions, and marked this question as a duplicate. Seem reasonable? Thanks for your input.

[sugab]

Facing segmentation fault on some apps after dist-upgrade, the ppa itself suggest to do ppa-purge for Ubuntu older than 18.04, see this: launchpad.net/~gnome3-team/+archive/ubuntu/gnome3-staging