Firefox/Firefox ESR has a inbuilt software that checks for new versions
and ask to update or update automatically depending on preferences.
icecatmobile-38.5.2.en-US.android-arm.apk
<https://ftp.gnu.org/gnu/icecat/38.5.2/icecatmobile-38.5.2.en-US.android-arm.apk>,
icecat-38.5.2.en-US.win32.zip
<https://ftp.gnu.org/gnu/icecat/38.5.2/icecat-38.5.2.en-US.win32.zip>,
and icecat_38.5.2-gnu1+7.0trisquel1_amd64.deb, that I just tested, all
lack automatic updating, this is a reason why some people rather still
use Firefox; because they cannot be sure if they use the latest IceCat
without manually comparing their running version with the latest release
in the FTP archive.
Can you please implement the update function?
--
http://gnuzilla.gnu.org