Custom ROMs used to be associated with speedy updates. That's not necessarily the case anymore. Technically, yes, someone somewhere will probably release an unofficial build with the latest update that you might feel comfortable using if you're very trusting and have nothing to lose if your phone malfunctions. But for those well-tested versions, you generally have to wait a bit longer.

CyanogenMod started pushing out nightly builds with Android Marshmallow not long after Google made the code available, but the project is only now ready to offer its first Snapshot release. This build is going out for devices that have had nightly builds for a while and have reached a point in development that maintainers would consider stable.

Screenshot from 2016-03-16 13-43-24

The changelog for this update isn't limited to those found within Android 6.0, such as the battery-saving Doze functionality. CyanogenMod 13.0 gets rid of encrypted Whisperpush text messages. Devices with the right hardware can protect certain content with fingerprints. Privacy Guard has been altered to comply with Marshmallow's new permission model.

Here is the full list of changes.

CyanogenMod 13.0 Changelog

  • A delta between 12.1 and 13.0 will show thousands of changes (Google’s, Qualcomms’s, Linux Foundation, CM Community’s, etc), but let’s take a look at the ones that you are likely to notice:
  • Whisperpush capability (encrypted SMS) – removed: Removed from CM software globally, no replacement
  • Settings > About phone > Advanced mode – removed: New behavior is to show all settings at all times.
  • Settings > Notification Drawer > Quick Settings – removed: New behavior is to control layout and options directly via QS panel via ‘edit’ tile or long-press of settings gear in the pull down area
  • QS panel configuration items such as ‘enlarge first row’ and ‘show weather’ now present on leftmost QS pane while in edit mode.
  • ‘Advanced location settings’ renamed to ‘Tri-state location’
  • Settings > Status bar: New controls for ‘Status bar icons’ (repurposing of SystemUI tuner from AOSP)
  • Settings > Lockscreen > Quick unlock – removed: No replacement; security constraint due to Android Gatekeeper
  • Settings > Sim Cards > manual provisioning switch (Multisim) – removed: Reliant on Qualcomm extphone. Currently no replacement.
  • Settings > About phone > Build date: Triple tap to access demo mode (developer/marketing feature to standardize renders).
  • Settings > Lock screen > Owner info – replaced: Replaced with ‘Lock screen message’ (AOSP change)
  • Settings > Memory: New screen (AOSP) to show memory usage over a selected period of time
  • Device specific implementations of double-tap-to-wake replaced by AOSP implementation: No major user impact
  • CM implementation of silent mode replaced by AOSP implementation
  • CM Protected apps: New folder UX for viewing protected content
  • Fingerprint support for accessing protected content
  • Enhanced ability to prevent access while retaining usability: A protected app can no longer be launched via Play Store
  • App notifications and services are not hampered by protection status
  • Power menu ability to swap System Profiles – removed: Engineering constraint – QS panel tile for System Profiles as functional replacement
  • New SMS/MMS Application: We have switched off of the Qualcomm based messaging application (Mms-caf) to the AOSP one (Messaging). Notable features such as ‘Quick reply’ are available, but there may be slight variations in UI/UX.
  • Permissions: Due to new permission model API in M, Privacy guard has been re-engineered to be compliant with this new environment. Primary permission request for ‘Normal’ security level permissions will be handled by our package manager for non Google users, or Google’s manager for those that opt for Googley bits. Users retain ability to control fine-grained permissions via Settings > Privacy > Privacy Guard
  • Snap Camera: Some devices now ship with an enhanced camera app based on Qualcomm’s Snapdragon camera. For devices that do not support the Snap app, you will retain the Camera2 app as in 12.1.

A Cyanogen Apps pack is not yet ready, but it's on the way. Expect CyanogenMod compatible C-Apps in a week or so.

There are various ways to go about updating your device. Hit up the source link below for guidance.