Due to quite a busy month and some complications, I forgot to publish 0.4.3
Docker image. This has been fixed now, with one problem. 

Users of Docker image should edit /data/maddy.conf and add the following
lines to it:

state_dir /data
runtime_dir /tmp

This is the result of build.sh no longer supporting in-executable
patching of default values for these directives.

Sorry for inconvenience!