Can't select .24 on Ubuntu 10.04 system

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http://askubuntu.com – I did a complete install of Ubuntu 10.04 and installed mythbuntu repos and mythbuntu control center. I set the repos to .24 and did upgrade. It would only access .23 instead of .24. I can't force an upgrade through synaptic package manager either. Any suggestions will be appreciated. (HowTos)