The Tizen powered Samsung Z1 may have received a lukewarm response in the beginning, but it seems like Samsung is betting big on the Tizen OS. A natural guess would be that a Samsung Z2 would succeed the first-gen Z1, but it appears as though Samsung will give it a skip to jump directly on to the Samsung Z3.
According to what we're hearing, the phone is expected to launch in the early part of the second half of 2015. It'll obviously be more powerful than the first-gen Z1; a quad-core 64-bit processor is what might drive the phone, along with a 5-inch display. What's good is that we don't have a lot to wait before we get to see the actual thing, if this rumour has any truth to it.
If you don't wish to wait too much before getting to know the whole story, here's what the phone might ship with: 2-megapixel front camera, 5-megapixel rear camera, a 5-inch screen and quad-core 64-bit processor as mentioned before, and lastly a 2000mAh battery.