We have a requirement to keep the history of assignments uploaded by students to compare the progress.
Student would be submitting the assignment until the teacher accepts it.
We are using moodle 2.9.
I had a look to create a custom module but files table doesn't have extra columns to differentiate between different version.
Any suggestions would be greatly appreciated. Please help.
This sounds like exactly what the 'attempts reopened' setting does in the assignments.
Each time a student submits some work and the teacher grades it, the teacher has the option of re-opening the submission. The history of all submissions is shown in a collapsed area at the bottom of the page, for each student.