The following link to the release notes for each type of Vault release. See About Vault Releases and Pre-release FAQ to learn more.
General Releases
General releases include all product enhancements and bug fixes that have gone into limited releases since the previous general release. General releases occur approximately every 4 months.
Limited Releases
Veeva releases feature enhancements and bug fixes to a set of "limited release" Vault production servers every 3 to 5 weeks.
Maintenance Releases
A maintenance release is a release that contains a typically small number of fixes for issues that are affecting customers.