We’ve upgraded to domino/notes 6.5 (spanish) and the mail templates uses this formula but Designet doesn’t recognizes it as valid (i.e. no syntax highlight).
As result we have problems related to this. We can’t see the Junk Mail view, the Follow Up view, …
I don’t know if it is related but in iNotes we see all tabs (mail, schedule, tasks, journal, …) duplicated,
As far as I know, and according to Lotus UK, the @HasFeature is new from R6.0.3 / R6.5 and checks the user licence to see if you are entitled to certain features in the R6.5 mail template design.
It is probably also there because the R6.0.3 and R6.5 mail templates are identical and it hides features such as Sametime awareness which is not supported by the R6.0.3 client.
I don’t know if this is the cause of your iNotes problem as I haven’t experienced this issue.