For the record, if you can already do a sudo apt-get update and sudo apt-get upgrade to get the new packages - I don't think you should be playing here....
huh - I only changed the one that was set to 600. Worked for me.
RayBe - open a command prompt and type:
sudo pico /etc/apt/preferences
(pico is a terminal text editor, you can use others like vim but pico might be easier).
You will see this section
# If our local package uses the same version as elsewhere, we take the one we have locally.
Package: *
Pin: origin
Pin-Priority: 600
Change it to
# If our local package uses the same version as elsewhere, we take the one we have locally.
Package: *
Pin: origin
Pin-Priority: 500
Save the file and retry.