The URL for the sixth beta (no mention of a beta tree in the URL) should have given the clue that after over 5 months, FetchTV have finally decided that version 4.8.04-11 will be a stable release. If your 8320HD is hooked up to the Net, a green SW. UPGRADE item will appear when you press the Menu button on your remote. Select that option and upgrade to this latest stable release, but if it doesn't work, there's always the USB stick route instead.
Some AVForums.com users are having trouble resuming playback of a recording that they'd pressed stop half way through viewing when using the 4.8.04-11 release - I've been unabled to reproduce this issue: all resumptions worked for me. Note that you can't resume during the first or last minute of a recording playback (don't ask me why!). Overall, though, it does seems quite a reasonable firmware release for once.