You are readmitted on conditions that you agree to in writing. In UJ's template, readmission is valid for that year only. Typical conditions are to pass your first-semester modules and reach at least a 40% progress mark in year modules, not cancel any modules, attend all lectures, tutorials and practicals, and attend Academic Development Centre workshops. Your outcome letter lists your actual conditions. Breaking them can lead to exclusion. Source: UJ appeals process document (template).