[8] It is capable of running different X and Wayland based user interfaces, such as Plasma Mobile,[9][10] MATE, GNOME, and XFCE;[11] later updates added support for Unity8 and Phosh.

[4] The project intends to support the mainline Linux kernel on all phones in the future, instead of the often outdated Android-specific fork, to reduce the potential for security exploits.

[19][20] Alpine Linux was chosen as the base distribution due to its low storage requirements, making it more suitable for older devices.

[21][4][22] In March 2024, the maintainers announced that postmarketOS would migrate from OpenRC to systemd as its init system for select user interfaces.

[35][17] After Corellium's Project Sandcastle ported the Linux kernel to some iPhone versions, postmarketOS was also seen to boot on it, although no persistent flashing is supported at the moment.

[40] The development process to make a new device compatible with the operating system consists of creating a phone-specific package using the pmbootstrap tool.