Time machine: Catalina backup with HD that have Mojave Backups

emiliano ballarini wrote:

Hi,

if I make a new backup with Catalina just installed, and I backup to an external HD used to Mojave's backup, do I risk losing the last ones?

Thanks for any reply.

Emiliano

If your new Mac inherits your backup history - Apple Support

https://support.apple.com/guide/mac-help/if-your-new-mac-inherits-your-backup-history-mh35732/mac