Motorola will not commit to monthly security updates for Android phones. The firm says it will bundle updates in a scheduled Maintenance Release (MR) or OS upgrade. Google will have released patches for the Android operating system this month. Motorola says it aims to keep phones up to date with Android security patches as quickly as possible but says it is difficult to do this on a monthly basis for all our devices because of the amount of testing and approvals that are necessary to deploy them, its difficult for us to do.”]
Source: https://grahamcluley.com/sorry-motorola-android-isnt-going-monthly-security-updates/