Project of new calendar foresees year with 13 months of 28 days

It is stopped has 50 years in the ONU the project of a new calendar where every month they would start in sunday and they would finish in Saturday. Each day of each month would always fall in the same day of the week. It would have 13 months of 28 days. The new month would have the Sun name and would be intercalated between June and July.