Cannot get nextcloud 13 installed using Docker on an armhf platform


I have a Odroid/Hardkernel HC2 (armhf).
I want to be able to use Nextcloud on that machine, running in a docker.
I have one partition (sda3) as a volume for Nextcloud data (2,3 Tb)
Mariadb is already running in a docker in the nextcloud docker network (accessible from nextcloud image).
I started the nextcloud docker like this:

docker run -d --network=nextcloud --name nextcloud -v nextcloud:/var/www/html/data -p 8080:80 nextcloud

I can get to the installation screen and fill out all the information (including mysql config).
After that I get redirected to a white screen and going to the server (port 8080) also results in a white screen.
In the logs I see this:

“reqId”:“YYREk9e6B1dPetI1vsUb”,“level”:3,“time”:“2018-04-15T13:35:37+00:00”,“remoteAddr”:“”,“user”:"–",“app”:“index”,“method”:“GET”,“url”:"/login",“message”:“Exception: {“Exception”:“Error”,“Message”:“Call to undefined method OC\\Files\\Node\\File::get()”,“Code”:0,“Trace”:”#0 \/var\/www\/html\/lib\/private\/Files\/AppData\/AppData.php(105):

It seems that it fails on /var/www/html/lib/private/Files/AppData/AppData.php line 105 which is: $node = $this->getAppDataFolder()->get($name);

My config file does have a line for the appdata folder:
datadirectory’ => ‘/var/www/html/data’,

The data folder is the mounted volume. It is reachable (as www-data) when I enter the nextcloud docker.

Never mind.
I switched to the version 13 (beta) snap. It seems to work now.