Do you know which emonSD version you are running? It may be listed on the Admin page. If it’s not there, there will be a file on the boot partition starting emonSD followed by the version…
We generally recommend upgrading to the latest emonSD image when upgrading old systems, see the process described here “Import using a SD card reader” Import / Backup - Guide | OpenEnergyMonitor
Thanks, yes emonSD-30Oct18 cant be updated safely from the interface and will require our more recent image. I would recommend downloading emonSD-21Jul21 and then using the guide to import your data from the original SD card.
The list of images that are safe to update via the interface are given here: EmonScripts/safe-update at master · openenergymonitor/EmonScripts · GitHub (we changed the directory structure significantly for images emonSD-17Oct19 or newer). Though it’s often best to do image updates at a more regular interval as you then get the OS updates as well.