Last week, we got a news that Motorola Moto Z will be getting Monthly Security patches, but it looks like that Motorola will not be issuing monthly updates.
Though Motorola will include the monthly security patches in OS upgrades, or in scheduled maintenance releases which will reach the devices in a month or two.
According to ArsTechnica, Here's the full statement by Motorola-
Motorola understands that keeping phones up to date with Android security patches is important to our customers. We strive to push security patches as quickly as possible. However, because of the amount of testing and approvals that are necessary to deploy them, it’s difficult to do this on a monthly basis for all our devices. It is often most efficient for us to bundle security updates in a scheduled Maintenance Release (MR) or OS upgrade. As we previously stated, Moto Z Droid Edition will receive Android Security Bulletins. Moto G4 will also receive them.
via- PhoneArena | Source- ArsTechnica