Last month, Purism announced that its Librem 5 Linux smartphone will ship in April 2019; earlier, it was scheduled to arrive in January 2019.
It seems that the developers will now get sufficient time to ship their phone with GNOME 3.32. In a blog post, the project urged the app developers to “use libhandy 0.0.4 and up, use GTK+ 3.24.1 and up and target GNOME 3.32!”
With the help of the new features added to libhandy and GTK+ fixes, developers can make their apps adaptive to both desktop and GNOME-running Librem 5 mobile device.
The post also mentions that many applications like Calls, Chatty, Fractal, and Podcasts are already using such adaptive capabilities; similar work is also being done for Settings, Games, Contacts, and Geary.
Currently, a GTK+ 3 widget library, libhandy and relevant widgets will be soon ported to GTK+ 4.
You can read this complete post and find the related links use for app development.