Not much to go on. Mr Trevaskus might be hinting at this, or he might not.
2 hours ago, Dave tweeted:
Don’t forget, in all the excitement of this week, we’re updating and improving the existing
#Lumia devices all the time.
All will be revealed, my people, all will be revealed!!
We could take this as an indication that perhaps the WP7.8 update (which brings some improvements including the new WP8 homescreen) will be launched this week for current Lumias. It was expected to appear after WP8 devices were launched. Hopefully we won’t have to wait too long.