I just received five 3850-48P-E switches. Some have 03.06.06E ((CAT3K_CAA-UNIVERSALK9-M), Version 03.06.06E) and some have 16.3.6 ((CAT3K_CAA-UNIVERSALK9-M), Version 16.3.6) . Why are they so different? I would like to maintain one version of IOS ...