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Notes has been designed to have the default ACL set to Author with no create or delete privileges.  Without this, people cannot edit the items in their person document like phone number, location, signature, picture, etc.  They also cannot delete the ID file from the N&A book after installation.  And worst of all, they cannot edit any groups that they have been given ownership of.  You should make the default ACL set to Author (with both delete and create turned off).
 Notes R3
Notes R3  Notes R4
Notes R4  Notes/Domino 4.5
Notes/Domino 4.5  Notes/Domino 4.6
Notes/Domino 4.6  Notes/Domino R5
Notes/Domino R5