Ok... I figured it out, and I'll share.
1. Connect Garmin with computer using your USB cable.
2. Download webupdater from Garmin.
3. Fully charge your collars and make sure your Astro has new or charged batteries.
4. Connect desired collar to the Garmin Astro.
5. Go to the dog list, and select the desired collar, and select show info.
6. Once in the show info screen, select menu again, and scroll down to upgrade dog unit.
7. Open the webupdater and click next, your device should show up in the webupdater screen if it connected to your Astro unit.
8. If your device is connected it will then tell you in the webupdater that your collar is being updated. Let it run, and repeat for each collar.
I'd suggest doing this soon because Garmin just came out with another upgrade for the units, Astro and DCs.
Hope this helps.
