We contacted Sony for a comment regarding which Xperia handsets will get an upgrade to Android L and we received the following as a response.
“We’re enthused by early reaction to the “Android L” preview. Whilst we can’t share roadmap specifics yet, we’ll continue to bring unique Sony software matched with the latest Android experiences to as many Xperia users as possible – so stay tuned.
Most recently, we’re pleased to have started rolling Google’s freshest Android version (4.4.4; KitKat) for Xperia Z1, Xperia Z1 Compact and Xperia Z Ultra.”
While their statement reminds fairly non-committal, we would expect to see the Z Ultra, Z1 (and Compact) and Z2 to receive it with an update for the Xperia Z seeming likely as the SOC is still supported in every way by Google thanks to it’s usage in the Nexus 7. Sony were the first manufacturer to update their phones to 4.4.4, so hopefully the updates should be coming within a month of the Android L rolling.