Hi.
What is the ESP32 core version you have installed in your Arduino IDE?
Go to Tools > Board > Boards Manager > Search for ESP32 and check the version you have installed.
Regards,
Sara

Hi Sara,
Installed Versions:
Arduino: 2.3.3
ESP32 3.0.5. 
To this moment in chapter 3 all the lessons from the LVGL-book compiled very slow but without errors and did what they should do. Great work. New in lesson 3 of the book is the use of Adafruits BME-lib (2.2.4) and Unified Sensor-lib (1.1.14). I used the newest ones, but did not compile without errors.  
Sorry I wanted only know about problems with the newest versions of the Adafruit BME-libs. But it seems that you dont know anything about that. Sorry for using your time.

Hi.
What board model are you selecting in Tools > Board?
I just tested the code and it is compiling just fine.
Did the previous project (3.1) compile without issues?
Regards,
Sara

I have a DOIT-DEVKIT-V1-Board with a red LCD-Board in action.
You are right with the 3.1. But I have left byside this and only read the Booktext. and went forward the 3.3
The errors definitely have to to with de Adafruit-Libs. If I am sitting at the program I will test it. 
 

You tested the code and he compiled well, so I am sure the problem is in my Installation. I will try a new Arduino.Installation with all the necessary libs. I will give you a reaction. 
Regards
Manfred 

You tested the code and he compiled well, so I am sure the problem is in my Installation. I will try a new Arduino.Installation with all the necessary libs. I will give you a reaction. 
Regards
Manfred 

How did you install the libraries?
Regards,
Sara

Hello Sara,
with the new installation of Arduino (renamed the old workspace and did a installation of all necessary libraries) all the Sketches from the book till 3.5 compiled without problems. Only the Sketch 3.3 was too large for my DOITDEVKITV1.  Surely should do with a stronger Chip (perhaps a S2-Chip) or another partition scheme. I have tested to take as Board “ESP32 Dev Module”. Because there are more possibilities for the Partition Scheme. The Sketch 3.3 compiled without problems, but the display stayed dark. But I will not give up, because the ESP32 has inough power to do it.
What I have learned from that: Doing a big new projekt only with a clean new Arduino-Workspace and a clean library. Being very careful with manipulations in the library itself. 
Thank you for your help and your patience.
Manfred

Hi.
For the sketch to big option, there are instructions in the eBook on how to proceed. 
 in Arduino IDE go to Tools > Partition scheme > choose anything that has more than 1.4MB APP, for example: “Huge APP (3MB No OTA/1MB SPIFFS“.
 
If the display continues dark, it is probably because the sensor is not wired properly. Please double-check the wiring.
Regards,
Sara

I wrote in my last post: The Sketch 3.3 compiled without problems, but the display stayed dark.  Today the Serial Monitor showed the reason. The Sketch couldn’t find the SSID, because of a typographical error. It stayed dark.
At last: it works.
Once more: Thank you for your help and your patience.

Great.
I’m glad the issue is solved.
I’ll mark this issue as resolved. If you need further help, you just need to open a new question in our forum.
Regards,
Sara