Chip shortage is hitting hard...
I've seen that the AP3015 of the first boosting stage (battery voltage -> 5V) was not available anymore.
I updated the schematic and board of the Zener-Tester / LED-Tester.
Replacing the boost converter with the Xinluda XB61040. It's pin compatible and even a bit cheaper.
Now, everything but the ADC (ADS1115) can be assembled by JLCPCB. (Just order the ADS1115 from LCSC and solder this chip by hand)