Marco's announcement on the new blogs site:
https://blogs.embarcadero.com/rad-studio-10-4-1-has-been-released/
Updated my wiki page with info on 10.4.1: https://github.com/ideasawakened/DelphiKB/wiki/D27.SYDNEY.10.4.1.0
RAD Studio 10.4.1 has a strong focus on quality improvements. Key quality focus areas include:
IDE
Delphi Code Insight (LSP)
Parallel Library
SOAP & XML
C++ Toolchain
FireMonkey
VCL
Delphi Compiler
iOS Deployment
New Features
Packages can now have an automatic version suffix (instead of manually updating and specifying the right version suffix with each new release)
New reader-write lock implementation via the new TLightweightMREW record
Faster and more lightweight than the TMultiReadExclusiveWriteSynchronizer (TMREW)
Works across all platforms (TMEW was a simple critical section on some)
Much improved support for multi-monitor desktop layouts and 4k monitors
The floating form designer has been removed
The Broadcast to devices option is now off by default
Platform Support Deployment to Windows Server 2019 now supported
The LSP based Code Insight much improved from its initial 10.4 release