Under the hood revision of the help system.
MedCalc version 23.2.0 was the last version that supports Windows Vista.

Updates:

Updated MPC Video Renderer to version 0.9.4.2373
Updated MediaInfo DLL to version 25.03
Updated internal MPC Audio Renderer
Fixes:

Fixed subs in SaveImage when video renderer gives topdown RGB
Several small fixes and improvements.
Translations
You can help improve and complete translations. See this topic for more info. There are several languages where recently added options have not yet been translated.

Overview of features
A lot of people seem to be unaware of some of the awesome features that have been added to MPC-HC in the past years. Here is a list of useful options and features that everyone should know about:

Play HDR video
This requires using either MPC Video Renderer (MPCVR) or madVR.
These renderers can be selected here:
Options > Playback > Output
With other video renderers, the colors will be wrong!
MPCVR is now included. MadVR needs to be installed separately. MPCVR also supports Dolby Vision. MadVR does not.
For optimal performance you should change the hardware decoder to D3D11 in LAV Video Decoder settings when using MPCVR on Windows 10/11, because this renderer uses DirectX11.
The installer of MPC-HC is very basic (and that will not change).
I therefore recommend using K-Lite Codec Pack. That includes MPC-HC and other essential components. It has a very advanced installation that can automatically create file associations, and helps you with easy configuration of important MPC-HC settings.
The Standard version should be sufficient for most people. Use Full version of you like to use MadVR.
Modern GUI Theme (Dark or Light)
Options > Player > User Interface
It is also possible to change the height of the seekbar and size of the toolbar buttons.
Video preview on the seekbar
Options > Player > User Interface > Hover type
Ability to search for subtitles
Press D for manual search.
Or enable automatic search in: Options > Subtitles > Misc
Adjust playback speed
Menu > Play > Playback rate
The buttons in the player that control playback rate take a 2x step by default. This can be customized to smaller values (like 10%):
Options > Playback > Speed step
Adjusting playback speed works best with the internal audio renderer. This also has automatic pitch correction.
Options > Playback > Output > Audio Renderer
MPC-HC can remember playback position, so you can resume from that point later
Options > Player > History
You can quickly seek through a video with Ctrl + Mouse Scrollwheel.
You can jump to next/previous file in a folder by pressing PageUp/PageDown.
You can perform automatic actions at end of file. For example to go to next file or close player.
Options > Playback > After Playback (permanent setting)
Menu > Play > After Playback (for current file only)
A-B repeat
You can loop a segment of a video. Press [ and ] to set start and stop markers.
You can rotate/flip/mirror/stretch/zoom the video
Menu > View > Pan&Scan
This is also easily done with hotkeys (see below).
There are lots of keyboard hotkeys and mouse actions to control the player. They can be customized as well.
Options > Player > Keys
Tip: there is a search box above the table.
You can stream videos directly from Youtube and many other video websites
Put yt-dlp.exe in the MPC-HC installation folder.
Then you can open website URLs in the player: Menu > File > Open File/URL
You can even download those videos: Menu > File > Save a copy
Tip: to be able to download in best quality with yt-dlp, it is recommended to also put ffmpeg.exe in the MPC-HC folder.
Several YDL configuration options are found here: Options > Advanced
This includes an option to specify the location of yt-dlp.exe in case you don't want to put it in MPC-HC folder.
Note 1: You also need to install Microsoft Visual C++ 2010 SP1 Redistributable Package (x86)
Note 2: yt-dlp nightly build (very latest version made daily)
Note 3: yt-dlp win7 compatible build
Besides all these (new) features, there have also been many bugfixes and internal improvements in the player in the past years that give better performance and stability. It also has updated internal codecs. Support was added for CUE sheets, WebVTT subtitles, etc.

Updated MPC-HC to version 2.4.1.0
Updated MPC Video Renderer to version 0.9.4.2373
Updated MediaInfo Lite to version 25.03
Updated Icaros to version 3.3.4 b1

[+] Небольшие улучшения.
[*] Обновлен список голосов для Google Cloud.
[*] Обновлены болгарские, вьетнамские, испанские, немецкие и турецкие языковые ресурсы (спасибо Костадину Колеву, Нгуен Нинь Хоангу, Фернандо Грегойре, Регине Мюллер и Феттаху Пинару).

Update LibreHardwareMonitorLib
Update translations
Fix a bug during automatic fan pairing
Update ADLXWrapper