In general, "no", if CDD requirements have not changed and if the changes to the fielded system are not radical (as in this case of a new open system sensor), most Milestone Decision Authorities/Decision Authorities will not require a repeat of the entire MS-B/MS-C process. However, the final decision will be made by the MDA/DA. But the MDA/DA will most likely depend strongly on the recommendation of the Program Manager who should recommend skipping the Engineering and Manufacturing Development (E&MD) phase (between MS-B and MS-C) for this change.