In 2014 Samsung launched the Galaxy Tab S. This tablet had a unique feature that made it stand out from the rest. It was the first tablet from Samsung in years that brought an AMOLED display. The time is right for a successor and one may not be that far off. Model code SM-T825 has been spotted in Indian import tracking database Zauba and it could very well point towards the new Galaxy Tab S. So far Samsung hasn't officially said when its going to launch a successor to last year's model.
The original Galaxy Tab S had model number SM-T800/805 so it seems only natural that the SM-T825 could point towards the new model. Chances are that this might be the version with 4G support.
It was recently reported that new tablets from Samsung will have displays with 4:3 aspect ratio. Though there's nothing to support this theory for now the possibility exists that the new Galaxy Tab S could have a 10.5-inch display with a 4:3 aspect ratio.
Last year the original Galaxy Tab S was unveiled in June. Its possible that the company may follow that timeframe again this time around.