- ESP-12F replaced with onboard components, no metal cover.
- 16MB flash (128Mbit)
- Built in ceramic antenna + external connector
- CP2104 USB-UART (changed from CH340G)
- Same dimensions as D1 Mini, compatible with existing shields
- Lighter and thinner than D1 mini
- USB + reset buttons moved to the top of PCB
- $1 more expensive than D1 mini