[application-package] bumped the default supported API from 1.88.1 to 1.89.1 #13738 - contributed on behalf of STMicroelectronics
[cli] upgrade the Theia build to use Typescript 5.4.5 #13628 - Contributed on behalf of STMicroelectronics
[core] added logic to delegate showing help to the back end process. #13729 - Contributed on behalf of STMicroelectronics
[core] added logic to don't reveal the focused element when updating the tree rows #13703 - Contributed on behalf of STMicroelectronics
[core] added logic to ensure globalSelection is correctly set when opening context menu on a tree widget #13710
[core] added to logic to ensure usage of user-defined THEIA_CONFIG_DIR #13708 - Contributed on behalf of STMicroelectronics
[core] fixed hex editor by updating msgpckr to 1.10.2 #13722
[core] improved WebSocketConnectionProvider deprecation message #13713 - Contributed on behalf of STMicroelectronics
[core] refactored auto save mechanism via a central service #13683
[core] updated logic to make browserWindow of splashScreen transparent #13699
[dev-container] added support for four previously unsupported dev container properties #13714
[dev-container] improved logic to show dev-container label in status bar #13744
[electron] updated electron to ^28.2.8 #13580
[navigator] added logic to handle isFileSystemResource context key #13664
[navigator] added logic to not show the new "Open With..." command on folders #13678
[notebook] added additional css to notebook output webviews #13666
[notebook] added basics for notebook cell drag image renderers #13698
[notebook] added logic to select next notebook cell on first or last line of editor #13656
[notebook] added logic to select the last cell when deleting selected last cell #13715
[notebook] added logic to stop execution when deleting cell #13701
[notebook] added responsive design for the main notebook toolbar #13663
[notebook] aligned commands with vscode notebook commands #13645
[notebook] aligned notebook scroll into view behaviour with vscode #13742
[notebook] fixed focus loss of the notebook editor widget when bluring a cell editor #13741
[notebook] fixed notebook cell divider size #13745
[notebook] fixed storing of the notebook-outlineview state data #13648
[notebook] improved notebook cell model lifecycle #13675
[notebook] improved support for creating new notebooks #13696
[plugin] added stub for registerMappedEditProvider #13681 - Contributed on behalf of STMicroelectronics
[plugin] added support WindowState active API #13718 - contributed on behalf of STMicroelectronics
[plugin] fixed github authentication built-in for electron case #13611 - Contributed on behalof of STMicroelectronics
[plugin] fixed incorrect URI conversions in custom-editors-main #13653
[plugin] fixed quick pick separators from plugins #13740
[plugin] improved vscode tab API #13730
[plugin] updated DropMetada and documentPaste proposed API for 1.89 compatibility #13733 - contributed on behalf of STMicroelectronics
[plugin] updated nls metadata for VSCode API 1.89.0 #13743
[remote] added logic to support plugin copying for remote feature #13369
[terminal] fixed performance issues in terminal #13735 - Contributed on behalf of STMicroelectronics
[terminal] updated logic to allow transitive binding for TerminalFrontendContribution #13667

<a name="breaking_changes_1.50.0">Breaking Changes:</a>

[core] Classes implementing the Saveable interface no longer need to implement the autoSave field. However, a new onContentChanged event has been added instead.
[navigator] The Open With... command now uses a dedicated OpenWithHandler to populate the quick pick. Adopters contributing an open handler need to explicitly add the handler to the OpenWithHandler (#13573).