Recovering data after OS 5 update

Have an EX4100 in JBOD.
Since OS move I cannot access the data (migrating disks to an ex2100 didnt work - needs firmware updates as not been used in years - not going there thou).
If Could at least still connect to TVs it wouldnt be a major issue.
Is there a way of putting disks in mybook duo cases and accessing the data?

I am so glad I never bought a dl4100 in the sales as the reason I have a NAS seems to have been nerfed (storing videos, music & documents in 1 location accessible by all the computers & devices…

@Muadib please check the following article

Thank you. I am hoping to get it sorted so they will. Currently the NAS is refusing access to twonky and plex.

Also noticed OS 5 doesn’t have a backup option?

@Muadib, the native Backup functions in OS 3 have become installable Apps in OS 5. You can install the ones you need from App Store.

Which app is it and will I still not have the same issue with the ex4100 refusing connection?

Is there not a way I can get OS 3 back please as none of these things were an issue.

More of a warning should be provided about the dangers of changing to OS 5?