There is sometimes confusion with FSB Order 547 or 555 regarding "foreign agents" or information security, though these are technically different agencies.
Historically, this order (specifically the version from 2017) established the rules for (MTO) for the Russian military. It covers: prikaz 555 ministra oborony
There may be specific local or older variants (e.g., related to military education or health standards) that use the same number. There is sometimes confusion with FSB Order 547