I did but Synaptic said it couldn't download the packages from the source. Apparently they had 404 errors on them. 
Most likely the server is updating. In Synaptic, in
Settings --> Repositories uncheck whichever is currently checked, and check another. Click
OK. Then,
in this order, click on
Reload,
Mark All Upgrades,
Apply, and again,
Apply, in the
pop up window.
If by chance you hit another syncing server,
repeat with a different one, until you find one that's fully updated. You want your whole system fully
upgraded, to date, before
adding any
new software. Any upgrades to what is installed will then be handled by the
next Upgrade session.
Each time you wish to
add new software, do the
Upgrade process first. We do a lot of continuous upgrading here, and everything needs to stay in sync, for the system to remain stable.
All the repo servers update on different schedules, not under our control. Most of the time everything just works. When you hit a syncing server, your two choices are, find one that's already done syncing, or wait for the original one to finish.
