US government on Microsoft 365 is split into two types:

  • Impact Level 4 (L4) or below: L4 covers data such as Controlled Unclassified Information (CUI) and/or other mission critical data that is used in direct support of military or contingency operations. It may also include data such as designated as For Official Use Only, Law Enforcement Sensitive, or Sensitive Security Information.
  • Impact Level 5 (L5): L5 accommodates data that is Controlled Unclassified Information (CUI) that may require a higher level of protection than afforded by L4 data. Severity of impact of data is considered by the information owner, law, or other government regulation. It can also be considered by the agency that owns the information and needing a higher level of protection than L4 provides. L5 data also covers unclassified National Security Systems.


L4 customers with ‘G’ SKUs work the same as the normal ‘E’ SKUs and work with the platform.


L5 customers (also known as GCC High or DoD) are more challenging, both technically (Direct Routing is configured differently) and for security vetting (US citizenship required for all people who have access). These elements mean that this level is not currently supported by the platform.