Silver sent an e-mail. Harry joined Twitter last week. You don't need a twitter account to read what's been posted.
And what has been posted is pretty interesting right off the bat. He's submitted an AH novelette set in 1920s Alaska for publication (not clear as to whom, though). 1920s AH is a good thing. Alternate Alaska can be a good thing, though I hope not a Russian Alaska. That would be more cliche.
A short story called "Zigeuner" will be published in Asimov's soon, but the exact issue isn't clear. Snap internet research informs me that Zigeuner is a German word for a Romani person, that is, a Gypsy. While this may be a WWII work, the fact that HT hasn't delved into the Romani perspective heretofore does pique my curiosity.