A Paperwhite will allow azw3 downloaded if registered. A K1, original Kindle, registered on its own would only allow very much inferior mobi/azw downloads.
K1 issues - No embedded fonts
- No CSS
- No user fonts
- Poor 4 level screen only 2 greys, peak grey and nearly black as it's a very early eink type
- Only 1/4 G storage with an SD slot that won't do more than 32G and might only do 4G.
- No WiFi
- The Whispernet died because the Cellular is EVDO only and is gone, so only USB transfer.
- Battery / Cell will be end of life.
- Only 167 dpi
The K1, K2, DX and DXG are all mobi/azw only. Only the DXG has a reasonable screen contrast. The DX models are slow and only 150 dpi, so though hyped for PDF being 9.7″, they are very poor for that. Only the K1 has the SD Card slot. The K2 only about 1.5G free.
They all have audio (speakers and 3.5mm jack), but it's pretty useless GUI.
The K1 is useless. Museum display or recycle
The K2 & DX are almost useless. Museum display or recycle.
The DXG has a better contrast but otherwise is similar to DX. Nearly useless.
Minimum Kindle to use as an ereader is the K3, if upgraded to last FW (3.4.3).
The K3 has WiFi so Whispersync may work, 16 level 167dpi screen with decent contrast (same generation eink as DXG) and about 3G free for ebooks. Does text to speech and azw3. WiFi. Some models have cellular, but the service is gone in most places. Browser now no use.
https://www.amazon.com/gp/help/custo...MQC26VQQMM8XSW