On the 26th of November 2020, Synology rolled out a new update 3 version for their DSM 6.2.3. The whole changelog is listed below. Keep in mind that you might not see the update for some time until the NAS/DSM picks it up. You can download them manually from this location:

https://download.synology.com/download/DSM/criticalupdate/update_pack/25426-3/

NOTE: Keep in mind to get the correct version for your NAS! You will not be able to install any other, but still, if the install is failing it might be the reason why. Also, remember that you can't roll back to an older version!

I have this running on my DS918+ (all-flash NAS) with Active Backup, Snapshot, VMM, Docker, and Plex packages.

There are no problems regarding any function of the NAS so far and the update was without any problems.

Version: 6.2.3-25426 Update 3
(2020-11-26)

Important Note
Your Synology NAS may not notify you of this DSM update because of the following reasons. If you want to update your DSM to this version now, please click hereto manually update it. Only Synology NAS with DSM 6.2.3 installed can be updated to this version.
The update is not available in your region yet. The update is expected to be available for all regions within the next few days, although the time of release in each region may vary slightly.
This update will restart your Synology NAS.

Compatibility & Installation
Photo Station must be updated to version 6.8.14-3501 or above to be compatible with this update.

What's New
Enhanced NFSv4 connection stability.
Increased the maximum number of IP camera channels on FS6400 to 150.

  • Fixed Issues
  • Fixed an issue where support ticket submissions might fail in a certain version of Google Chrome.
  • Fixed an issue where Windows 10, version 2004 virtual machines might fail to power on when users select UEFI as the firmware.
  • Fixed an issue where there might be network disconnections on Virtual DSM.
  • Enhanced the stability of SSD caches when multiple processes are accessing the same cache at the same time.
  • Fixed an issue where CMS managed servers might not connect to the CMS host after they restarted.
  • Fixed an issue where disks in Resource Monitor performance charts were not displayed in the correct sequence. Affected models include:
  • 21-series: DS1621+
  • 20-series: FS6400, DS1520+, DS920+, DS720+, DS420+, DS220+
  • Fixed an issue where when users access files on DSM using Windows software via SMB, system performance might be affected. This is because of Windows software's continuous attempts to access the shared folders to which it has no permissions.
  • Fixed an issue where Windows File Explorer might not update file deletion or removal in real time when folders are mounted via SMB.
  • Fixed an issue where the system might not report the power status correctly on SA3200D.
  • Fixed an issue where the setting pages after first-time DSM installation might not launch on Synology NAS models with multiple LAN ports.
  • Fixed an issue where users were not able to empty the recycle bin of the "usbshare" shared folder.
  • Fixed an issue where administrators were not able to change the "User must change password at next logon" setting via Windows RSAT.
  • Fixed an issue where domain users could not be added to built-in groups via Windows RSAT.
  • Fixed an issue where enabling the "Collect debug logs" option for SMB might result in excessive system space usage.
  • Fixed an issue where the system might send incorrect port forwarding notifications after a restart.
  • Fixed an issue where SHA-1 certificates might disappear when users click "Upgrade certificate".
  • Fixed an issue where DSM might block users' IP addresses and create excessive logs when they tried to sign in after re-installing DSM.
  • Fixed an issue where incorrect drive compatibility information was displayed after drive migration.
  • Enhanced the stability of network interface cards on certain models.
  • Fixed an issue where links in password reset emails did not work when the URLs exceed the maximum length.
  • Fixed an issue where packages did not update automatically due to dependency problems.
  • Enhanced SAS controller stability during system shutdowns.
  • Fixed multiple security vulnerabilities. (Synology-SA-20:26)
  • Supports Let's Encrypt ISRG certificates.