According to the list of supported cameras, that camera is supported in 8.3, which is the latest version. If you download DNG converter 8.3 you should be able to convert your files.
I tried the Adobe DNG Converter 8.3. All options on the program were tried to get 8-bit DNG. However, the raw format is converted to the 16-bit DNG file. I want to convert the raw format to 8-bit DNG file. Is there any option that I can use ?
If you use the lossy compression option, the DNG file will be saved in 8-bit mode. Otherwise it will be a 16-bit file. The purpose of the DNG converter is to take the raw image data and place it, unchanged, in a "standard" file format. Cameras save that raw data in anywhere from 10 bit to 14 bit images. So, it is necessary to use the lossy compression option because that will change the data and enable the DNG converter to create an 8-bit image.
And, just to clarify, regardless of the bit depth of the original image, Camera Raw and Lightroom both open raw images into a 16-bit workspace. I normally convert to 8-bit at the end of my Photoshop session or when I export from Lightroom.