These versions contain a fix for an issue that could sometimes occur and abruptly close the VNC session.
To upgrade, you only need to start a new instance. If you have any data you wish to back up, you can put it on an EBS volume and then attach that volume to your new running instance. Mount the volume and copy over any desired files. Users can also utilize Ubuntu’s built in backup feature to create backup files of desired folders on a volume which they can similarly attach to the new instance and use the backup program to restore those files from the volume.