Please write a paraphrased version of the text:
The transitional arrangements set out in the Accession Treaty of 2003 allow for limited derogations from the principles set out in the preceding paragraph, during a transitional period which will irrevocably come to an end on 30 April 2011.
During the transitional period finally expiring on 30 April 2011, the transitional provisions laid down in the 2003 Treaty of Accession allow slight deviations from the principles referred to in the previous paragraph.