Originally Posted by mherdeg

Star Alliance upgrade inventory comes out of the same place as award inventory. So a quick check for whether or not a *A upgrade on a B fare will go through is whether or not united.com will sell you a Saver business-class award seat on that LH flight.

Frustratingly, *A awards have no waitlist and need to be placed 24 hours in advance, so if they only open up inventory at T-24, you are out of luck.

If you don't want to be constantly polling, Expertflyer will sell you a monthly subscription that includes availability alerts that would probably send you an e-mail within an hour or two of space opening up (provided that you are very careful to set it up to look for the right inventory — it can be tricky).

There is plenty of saver business-class availability on LH, but you are currently tied to a *specific flight* on a *specific day* in peak travel season, which can be dicey for revenue-management reasons. Inventory may open up any time from now to the travel date, with a particular bias towards the 24-48 hours before travel. Keep checking.