The Patents Act 2004 (Commencement No. 4 and Transitional Provisions) Order 2007 (SI 2007 No. 3396) finally brought Sections 1-5 of the Patents Act, 2004 into force on 13 December 2007, the same day on which the revised European Patent Convention also entered into force. Two of the most important changes dealt with are the patentability of substances for the use in treatment or diagnosis and the post-grant amendment of patents.