I also had my update tab disappear
That's actually normal now in the beta build of Impulse V2. They're trying to make it less cluttered, so unless there's an update to download the tab shouldn't appear.
Its listed as 1.10.036 - but after running into the multitude of bugs in the game so far I can only be thankful that it is not that much of a problem this time, and only because I was able to solve it..with your help:P
Well, 1.1 fixes I think pretty much every bug that's been known and some new ones that were discovered during testing. It should be pretty near smooth sailing.
Edit: I think it warned about cancelling because it needs to re-log on with different settings, but I can't say for certain since mine is already updated so unchecking it wouldn't do anything.
Also for the sake of completeness, if you're running Vista, some people reported it hangs on "Verifying" after the download finishes, if that's the case and it takes too long you should exit Impulse and run it with Admin privileges (right click > run as admin). You won't need to download again, it should pause when you exit and you'll be able to resume extraction. This is just going by what some other folks talked about on IRC so mileage may vary or may not even happen 