It definitely includes email. It seems like maybe you can go back even if you affirmatively upgraded? Haven't tried obviously but the Google page about it seem

It definitely includes email. It seems like maybe you can go back even if you affirmatively upgraded? Haven't tried obviously but the Google page about it seems to indicate as much. https://support.google.com/a/answer/2855120?hl=en https://support.google.com/a/answer/2855120?hl=en