The opposition to the grant of a patent under the Indian Patents Act, 1970, as amended by the Patents (Amendment) Act, 2005. The appellant (the patent holder) contended that after ... the rejection of a "pre-grant opposition," the respondent (the opposer) should have filed a "post-grant opposition" under Section 25(2) but did not do so. Meanwhile, the respondent argued that they had correctly filed an appeal in the High Court under the unamended provisions.