@dbemowsk It is. It's a german chain though ;)

How do you plan to do that? Compnonents?

@kalina You're right. But it is no problem for me to solder in the ESP-12. So thank you.

One question: will I be able to use Wifi, Serial OR (not and) LAN if I follow the steps from your instruction? As in just change jumper positions and use the other one? Does the sketch support that?

Could you please describe the "WLAN way"? Tank you.