Gimp and transparency in GIF images

["[KS]" <lists04@fastmail.fm>]

Hi,

I'm trying to create a gif image with a drop shadow which is 80% opaque
with Gimp 2.2.8. When saving the image as gif it asks to convert it to
an indexed image. The resulting image (gif) does not give me the
transparency that a png gives. I noticed that earlier there was a need
to download the gif plugin because of licensing. However, the Finnish
server which hosted the plugin gives me a zip file containing a text
file and it indicates that the plugin is not need now.

Can somone point me how to make the gif image with transparencies?

Thanks,
/KS