Further,according to the appellant,"pre-grant opposition" was filed by respondent no.3 under S.25(1) on 21.3.05.According to the appellant,though the Patents (Amendment) Act,2005,amended S.25 by enacting the amendment on 4.4.05 the said amendment was brought into force w.e.f.1.1.2005 and,therefore,it was open to respondent no.3 to challenge the grant of patent by invoking S.25(2) of the Patents Act,1970.According to the appellant,with the change in the structure of the Act providing for only one statutory appeal and that too only against the order granting patent under S.25(4),the appeal filed by respondent no.3 against pre-grant opposition order was not maintainable on 19.10.06 by which time,as stated above,S.25 stood restructured providing for a dichotomy between "pre-grant opposition" and "post-grant opposition