Do you mean R4SDHC from www.r4sdhc.com or R4-SDHC from www.r4i-sdhc.com ?
The former has its latest R4SDHC V2.10T version. Its latest kernel is R4SDHC V2.10T09.
It does not support DSi series, and does support SDHC tech.
And i paste out its main features below.
R4SDHC V2.10T series products are brand new products, greatly updated for both software and hardware. Compatible with all latest Nintendo games perfectly, faster game loading speed, customization mode added, customizing the sequence of the games, music and files freely. High precision finish chip to speed up the game running speed, lower power consumption. The mold of the outer shell is made of the imported ROCHS material in order to assure the good connections with R4 SDHC V2.10T and the console.
R4SDHC V2.10T Functionality
* Able to memorize and restore to the previously selected game or application after restarting machine and soft reset.
* Sleep mode function, for power saving and longer standby time
* Multi-languages are optional, they are Simplified Chinese, complicated Chinese, English, Japanese, French, German, Italian, Spainish and Dutch.
* Friendly interface, easy to operate.
* Realtime smart help windows.
* Integrated the latest Moonshell 2.0 Beta version.
* Game compatibility: 100%.
* No need to flash. Built-in launch Slot-2 (gba) function.
* Support SDHC micro sd cards (4GB?8GB?16GB?32GB).
* Support DMA read and no lag while using any microSD card.
* Support FAT16 and FAT32. Files can be transferred with PC, PDA, Cellphone and Camera.
* Support clean rom and drag-drop to play. Fast loading.
* Support NDS and iDS games. DS games can run on any DS versions.
* Files are to be saved directly to TF card, copy or restoration is not required.
* Automatically recognise saved new game types, no need to update the database.
* Support moonshell and home brew.
* Power saving design. Enter optimized mode automatically.
* Double screen UI, abbreviated picture and game title display, button and touch operations.
* Easy to use, setting or adjustment is not required.
* Support Wi-Fi, rumble pack and browser expansion.
* UI background can be changed.
* 4-level brightness adjustment.
* Support soft reset.
* Support AR cheat code.
* Support soft-reset of moonshell 2.0 (back to main menu of R4 NDSI by pressing START button).
* DLDI auto-patching.
* Support Download play.