Oneplus is bringing new OxygenOS 3.2.6 for the OnePlus 3.The update is incremental so please wait patiently until it reaches your device.It is also warned that rooted users will face installation issue.

The new update includes:

• Optimized voice call quality of some IM applications.
• Improved adaptive brightness performance
• Improved camera quality
  • Fixed occasional green/yellow issue
  • Optimized white balance
  • Improved 1080p video recording
• Addressed some bluetooth connection problems for vehicles
• Allows third party application to modify ringtone
• Optimized battery consumption when scrolling
• Optimized touch accuracy when playing games
• Added DozeMode switch in Developer options
• Added PocketMode switch in Display settings

If you can't wait until the update arrives to your phone,you can flash the zip file manually.

OOS  3.2.6 zip file :  https://drive.google.com/drive/folders/0B9NcF-m0L4C-Q0hoU2ZjOHN4X1k?usp=sharing