ReadyNAS RNDU6000 Docker daemon not running after upgrade to 6.10.5 (from 6.10.4 Hotfix 1)

This morning I noticed a firmware upgrade and installed it. 

After the reboot I found Docker CLi app no longer present and went to the console. docker ps gives an error saying

root@storage:/var/log/readynasd# docker ps
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Reinstalling the cli app gives an error. Looking at the install log it says:

root@storage:/var/log/readynasd# more install_debpkg.log
Install app docker-cli-rnapp
fv-app-install-utils.c:101(info) [docker-cli-rnapp](0%) prepare
fv-app-install.c:674(error) fv-app-install (docker-cli-rnapp): error code [100]: Reading package lists...
Building dependency tree...
Reading state information...
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 docker-cli-rnapp : Depends: linux-image-extra but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

fv-app-install-utils.c:121(info) [docker-cli-rnapp](0%) abort

Checked that linux-image-extra package:

root@storage:~# dpkg -l | grep linux-image
ii  linux-image                    4.4.218-610050003              amd64        Linux kernel image
root@storage:~# apt-cache show linux-image-extra
Package: linux-image-extra
Architecture: amd64
Version: 4.4.190-610040005
Priority: optional
Section: kernel
Maintainer: Justin Maggard <justin.maggard@netgear.com>
Installed-Size: 30000
Depends: linux-image (= 4.4.190-610040005)
Filename: dists/6.10.5/main/pool/l/linux/linux-image-extra_4.4.190-610040005_amd64.deb
Size: 6501912
MD5sum: 24eb0f037151fe82793588fb804e354a
SHA1: 7089fd3c6b14b6cc1e47cd7ce657190619364821
SHA256: 07e0a30e19920ae6f2d47b705de0cc8e557fe64f461799db534b6d98c8ac907b
SHA512: c67047acbec4d567c5258e35c4474bf95dbdc5fc99534c4ec5974e1c49d2b8a09d460951da2f0ca5b700a5866900a81f6cc9798bcd94fd6fb6d061cb40991a26
Description: Linux kernel extra modules
 This package contains extra Linux kernel modules for the ReadyNAS kernel.
Description-md5: c6c42413d09a77f617e40d5b9c348bdf

It has been running fine for years and this update has broken it :(

Any pointers?