GSAS made some recent changes which allow students to shift their priority years to any combination within G3, G4, G5, and G6 years. This allows students in the Study of Religion to do research work earlier in their program, if they have secured alternative sources of funding. Read the guidance here: https://gsas.harvard.edu/news/stories/gsas-implements-enhancements-fundi....
See also: Graduate Program FAQs