[xubuntu-users] Upgrading from 14.04 to 20.04 and owner/group ID changed. How best to fix?

[Ram Ramesh]

Hi,

   I was with mythbuntu 14.04 and decided to upgrade to xubuntu 
20.04+mythtv. One striking thing I noticed is that all  user/group IDs 
have changed between the versions that makes all prior recorded program 
owned by strange users/groups. This will cause glitches in 
recording/watching programs.  I need to fix this.

  I cannot chown/chgrp to 20.04 defaults, as I still dual boot to 14.04 
as 20.04 upgrade is going to take a while (many things do not work and I 
may have to abandon upgrade in the worst case) I still need to have 
owner/group IDs on file system preserved. Given this, the best choice I 
have is to change the ID and group of 20.04 install in /etc/passwd or 
/etc/group. Is this not advisable? Specifically, is there an implicit 
assumption about IDs in the installation and maintenance of 20.04 xubuntu?

   If ok to change IDs to match the way it is in mythbuntu 14.04, is 
there a known solution available before I come up with one?
Also, is it as simple as merging old /etc/passwd or group with 20.04 
default ones? I mean, are there other places where this information is 
stored and I need to change there too?

Regards
Ramesh