blog.crox.net

Add this line to /etc/apt/sources.list:

deb http://deb.debian.org/debian bookworm-backports main

Run:

# apt-get update
# apt install -t bookworm-backports libheif1

This solves the issues encountered when decoding HEIF (.heic) files produced by iPhone / iOS 18, causing for instance rendering in Nextcloud to fail.

This page has more details on using Backports.