According to SamMobile, the Samsung Galaxy Tab S2 will be announced this coming June. There will apparently be four variants of the tablet. There will be an 8-inch model and a 9.7-inch model, with both having WiFi and WiFi + LTE respectively, for a total of 4 variants.
They will apparently be released worldwide, including the US, Canada, European markets, China, Latin America, Hong Kong, Korea, and India, though this information seems to be unconfirmed.
The Galaxy Tab S2 will have a 4:3 aspect ratio and will be even more thin than the iPad Air.