Bitnami images are up-to-date in the sense that we upgrade and release a new image when there are new versions of the applications available. I'm afraid that there is no built-in process for automatic updates for running VMs.
We have documented the process to update the Pimcore installation here.
Unfortunately, our Pimcore solution does not Redis nor Scale-Out. I'm not familiar with Scale-Out, could you please provide us with some link to its documentation/setup instructions?