Error in GTK Client

Hi

On an Ubuntu Xenial I have the following error messages on the GTK client in version 5.5

On the right click in a list view:
AttributeError: 'Selection' object has no attribute 'set max content height'

On the display of search filters:
AttributeError: 'popover' object has no attribute 'popup'

Does someone have an idea ?

Regards.

Which gtk version does have Ubuntu Xenial?

Those methods exist since Gtk 3.22:

Gtk 3.22 has been released in 2016 and it is the smallest still mainatined release: GTK - Wikipedia
In Ubuntu Xenial, it is version 3.18: Ubuntu – Error so Tryton can no more be used on it.

Thank you for the answer