
The following new features are introduced
- Initial Release of modern device management for macOS: please take a look at my Blogarticle „Is Symantec entering the Mobile Device Management / Mobile Application Management space again?“ – most of this is still valid. I hope that the MDM management capabilities will be extended to iOS and Windows 10/11 in one of the upcoming releases.
- One of the best features introduced with 8.6 RU2 is the ability to add Packages to the Preboot Environment with a simple checkbox. I´ve created a feature request in 2019 for this feature – see this Blogpost.
Before the 8.6 RU2 release it was also possible to add Packages into WinPE but it was necessary to modify the default.bdc and another file (WinPE10_x64.ini). Now everything you need to do is to check the required Packages and bring them into the „right order“. Some of these packages have dependencies which require a specific package to be added first before a dependent can be applied.
The order is important to get the Packages added correctly and to be able to use them in WinPE. If the Packages are not in the correct order you will see errors in the Bootwiz.log file on your SMP or NBS Server and the Package is not added to the Preboot Environment.

- WinPE11 is now supported. There are Post 8.6 RU1 Updates available to use WinPE11 with the 8.6 RU1 release.

- Only Microsoft Edge and Google Chrome Browser are supported from this release onwards.
- A very useful feature got introduced when using Maintenance Window. The ability to use a Power Control action as last action in a Maintenance Window. You can find this new Feature in SMP Console -> Settings -> Agents/Plug-ins -> Maintenance Windows

- Another feature added to the Power Control Task is the ability to send a notification message and allow the user to defer.

- Support for multiple lines of text in Task UI

- Detailed Client Information in Symantec Management Agent: Computer Model, Computer Manufacturer, Edition, Version, Last Boot and Current User

- CVE ID Based Patching and Reporting

- Patch Management Support for Office 2021, GIT and Windows Defender


- Ability to define Custom OS Types: you can find the new OS Definitions in
SMP-Console -> Settings -> Deployment -> Operating System Definitions

- Ability to use Site-Specific Initial Deployment Settings


- New options when creating a Standalone Inventory Package (use Communication Profile, Passwort Protect the Package, Secure collected Inventory data and define an expire date.

- In the Advanced Options of the Standalone Inventory Package you can configure Logging Settings.

Reference:
For a complete list of new Features and Fixed Issues check the 8.6 RU2 Release Notes