Archived copies, kept so that the terms in force at the date of any invoice can be read as they stood at the time. Each invoice states the version it was issued under.
SHA-256 45e5140938d0f7d5c072c75058bd3ef98ab0a55e9d55e5672a40cb9ff5afce6c
SHA-256 41ad5679812c734e0bdc2768544888b8b620a3c8cd612317d846aaaf9e5b2521