Does deleting old file incrementals affect future ones?

general discussion
1

I am running ordinary daily file backups and was wondering if deleting old incrementals affects the future ones?
For example:
Day 1 - Full Backup
Day 2 - New files 1-10
Day 3 - New files 11-20
Day 4 - New files 21-30 etc.

Now if I delete Day 2 and Day 3, can I still use Day 4’s backup to retrieve files 1-20 if necessary?
I am assuming that UrBackup is smart enough to only delete links to the files, not the files themselves, or they would never be recoverable, is this right?

2

yes