Microsoft has pushed Windows 10 Mobile/PC Build 14393.2189 (KB409319) to those on Anniversary update. You can check the update availability by going to Settings–>Update & Security–>Windows update–>Check for updates.
Coming to what is there in changes/fixes/improvements, there are no significant changes. But there are lots of fixes and improvements.
You can check the full changelog of Windows 10 Mobile/PC Build 14393.2189 (KB4093119) below.
Windows 10 Build 14393.2189 (KB4093119) Changelog:
This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:
- Addresses an issue that generates an access violation on certain pages in Internet Explorer when it renders SVGs under a high load.
- Addresses an issue with printing content generated by ActiveX in Internet Explorer.
- Addresses additional issues with updated time zone information.
- Addresses an issue where user accounts are locked when applications are moved to a shared platform using App-V (e.g., XenApp 7.15+ with Windows Server 2016, where Kerberos authentication isn’t available).
- Addresses an issue that might cause the App-V service to stop working on an RDS server that hosts many users.
- Addresses an issue that, in some instances, prevents Internet Explorer from identifying custom controls.
- Security updates to Internet Explorer, Windows app platform and frameworks, Microsoft scripting engine, Microsoft Edge, Windows graphics, Windows Server, Windows wireless networking, Windows Hyper-V, Windows kernel, and Windows virtualization and kernel.
 available for Anniversery update now. Changelog){kind=link}