We’ve just released a new stable firmware for the Ultimaker S5 and the Ultimaker 3 (Extended).
Use your Ultimaker printer with Ultimaker Cura 4.0 and an Ultimaker account, and you can make use of the remote ‘cloud’ printing feature. This lets you print from outside the realms of your local network with an Ultimaker 3 or Ultimaker S5 via your Ultimaker account. There are also some other features detailed in the blog.
It *is* possible to downgrade a UM3, @kevin-osborn, but it's difficult because the whole process changed in 5.2. So if you are a version older than 5.2 it's easy to downgrade and if you are at version 6.0 (in the future some day) it should be easy to downgrade to 5.2 but no lower.
Anyway to downgrade across this boundary is more involved.
You need to remove the bottom cover and you need a micro-sd card and special software on your pc/mac/linux machine to create a boot pa