Add note about root requirement (#57)

* Add note about root requirement

* Update README.md

---------

Co-authored-by: Madelen Andersson <madelen.andersson@axis.com>

README.md

@@ -36,6 +36,15 @@ and [Buildx](https://docs.docker.com/build/install-buildx/) installed.
 The Docker Compose application is available as a **signed** eap-file in [Releases][latest-releases],
 this is the recommended way to install this ACAP.
 
+> [!IMPORTANT]
+> From AXIS OS 11.8 `root` user is not allowed by default and in 12.0 it will be disallowed completely. Read more on the [Developer Community](https://www.axis.com/developer-community/news/axis-os-root-acap-signing). \
+> Docker Compose ACAP 1.3.1 and previous, requires root and work is ongoing to create a version that does not.
+> Meanwhile, the solution is to allow root to be able to install the Docker Compose ACAP.
+>
+> On the web page of the device:
+> 1. Go to the Apps page, toggle on `Allow root-privileged apps`.
+> 1. Go to System -> Account page, under SSH accounts toggle off `Restrict root access` to be able to send the TLS certificates. Make sure to set the password of the `root` SSH user.
+
 The prebuilt Docker Compose ACAP application is signed, read more about signing [here][signing-documentation].
 
 Download and install any signed eap-file from [prereleases or releases][all-releases]