The NAV3 and NAV4 range of models use MyDrive Connect. MyDrive Connect is compatible with 32bit and 64bit versions of Windows XP/Vista/7/8/8.1/10 preview and with most Mac OS X versions. The internal flash memory or the memory card content of the device cannot be accessed through USB for security reasons (modified applications would easily accept a map that wasn't sold by TomTom). The device can update itself by getting files through the HTTP protocol over USB. The support app is nothing more than a proxy on the PC buffering the download. So far the security achieved using this mechanism has not been broken yet. Also, the usage of the non-FAT/FAT32 file system brought stability improvements in device operations.