The 7.8 update is upon us, but it is a phased rollout so you might not get it straight away. Luckily there is a trick to get it immediately, assuming it is actually available on your phone. All the Nokia Lumias are getting it. Some folks are having a little trouble with this trick, so this is how I did it.
1) Turn off data on your phone ( 3G and WIFI) – this is important otherwise it checks via the phone.
2) Connect the Phone to the PC via USB cable (it doesn’t matter if the phone is with or without SIM Card)
3) Zune loads up automaticaly or if not just open it
4) Open also the Network Connections icon and look for your active internet connection on the PC – LAN connection or WIFI connection.
5) In Zune, select Update. It will begin searching the server for an update
6) Count 3 or 4 seconds, hit “Disable” for the LAN or WIFI connection of your PC (or use e.g. the wifi switch on a laptop).
7) You will see the message “An update is available” on both the Zune and phone.
If you get the message “Your phone is up to date” you weren’t quick enough. If you get an error message with a code that “Zune can’t connect right now try later” it’s because you were to quick. I usually got the desired update message on the 2nd-3rd try
8) Enable your network and Click Ok to update the phone.
Note that there are 3 updates, the final one is 7.8 (why I do not know as they are supposed to be cumulative). So you may have to do this 3 times in a row, but you will get them and also won’t have to wipe the phone – this just upgrades it and keeps all your stuff.
And here she is on my Lumia 800:
Update: After doing this, 2 weeks later I received a further update notification for my Lumia 800. This updated only the firmware, so I can only assume that if you force the update, you may not get included firmware udpates until if and when the OEM releases the udpate officially for your device.