Nokia T21 is the upgraded version of the Nokia T20, the first tablet with the Nokia brand that was released in a while. The last Nokia tablet was announced back in 2014 and it was Nokia N1 running on Android.
Nokia T21 is bringing many improvements over T20 like the support for HD streaming, the support for the active pen (stylus) and a Second screen for PC. There is also a bit faster 18W charging and 8 MP selfie camera as opposed to the 5MP one from T20. Check the specs here in the announcement post.
The design is also new, but the question is if the internal design has changed. To see that someone needs to disassemble the device and make a video of it. TechnoRabin posted again a video instructions for the repair dudes to disassemble T21 without damaging it.
The process starts by loosening the adhesive with a heat plate or gun. With the LCD screen gone, the internal parts are visible nicely. There is a large battery placed centrally with a motherboard and speakers placed above it. The speakers are again connected by cheap-looking wires instead of a cable ribbon. The battery is glued tightly to the aluminium frame and ethanol is needed to loosen the adhesive holding it. It looks that the upper part where the antennas are is made of plastic, while the bottom part that holds the battery is made of aluminium.
Overall, this is a nice looking affordable laptop. Not a big improvement over the T20, but a significant one since now its 2K screen can be used as a second display for your PC.