It's still not even showing up in Steam for me to download!
Did you buy Odyssey on Steam? If you didn't (like me, only bought the base game + Horizons on Steam), the update is two-step: 1) Update the game via Steam. This should be a download about 1.7GB in size. 2.) Open the launcher Steam installed. It is usually found under <steam_library>/steamapps/common/Elite Dangerous and named EDLaunch.exe. Start it and it should appear with golden text instead of Horizon blue. In the list, Odyssey should appear as the topmost entry now. Select "install" and there you go.
Thats's how I upgraded two machines by now. I bought Odyssey Alpha from the Frontier Store. Don't know how it works if you bought everything from Steam, but might be worth a try.
HTH, O7,
