Progress this Week This week I worked on InitialAssignments, AssignmentRules and LocalParameters. All these features are supported by the simulator and parsers now and I have verified this with tests from the Core Semantic SBML test suites. Some of the tests fail because I didn't account for the fact that amounts and concentrations of species are optional, and can be defined by AssignmentRules instead of being specified while defining the species or through InitialAssignments. I'll work on this in the coming week. Progress so Far As per discussion with my project mentors, we have now diverged from the initially proposed timeline. The first half was completed as proposed and the last two weeks were spent in building support for more SBML features instead of the Runge-Kutta-Fehlberg integrator. Plan for the Coming Week Fix the issues with tests described above Implement the Runge-Kutta-Fehlberg Integrator