The release of build 10586.164 is up from build 10586.122 release six days ago.
The site msmobile.pl says the expected features of this new bug fixing release include:
- Faster saving of screenshots
- Smoother video playback
- Opening of PDF files in Edge improvements
Microsoft is likely to publish a full changelog of fixes and improvements on their blog and we'll follow up this article with a full listing of what is new when available.
To grab the update head into Settings > Update & security > Phone update > Check for updates. Users must be enrolled in the Insider program using the Windows Insider app.
For those on the Lumia 650, 950 or 950 XL and who are in the Fast Ring you will not see an update as those phones are on the 14xxx branch for Redstone, whereas this release is on the more stable 10586.xxx branch, which is pre-Redstone.