As for what's on the table, Sonos didn't give any hints. The oldest hardware in Sonos' lineup at this point is the Playbar home theater soundbar and the Play:5 speaker. They both sound excellent still, but neither has built-in voice control like the newer Sonos One and Beam speakers. They're also certainly using older components that will eventually lead to them missing out on future features, like the AirPlay 2 update that rolled out last year. The Play:5 did get AirPlay 2 support, but the older Playbar and Play:1 didn't.
Sonos also discontinued the mid-tier Play:3 last year, which means there's a big price gap between the $200 Sonos One and $500 Play:5. Whether or not the company speaker that's notably better than the One that also doesn't make too many customers choose it over the more expensive Play:5 remains to be seen, as the Play:3 felt like an odd duck in the Sonos lineup for a while before it was ultimately discontinued. But something a little bigger with more bass than the Sonos One would be a nice addition to the lineup.
Given that the Berlin September briefings are happening just days before IFA, it seems like a safe bet that whatever new gear Sonos has to show off, we'll see it all revealed in early September at the show. Until then, start the speculation engines.