Attach a picture of the board that you have and I will verify if it is an STM32 Blue Pill, or something else.
If you know the values to enter into the Online Configuration Generator, then there are very little risks. You will need to reenter a few things after you first power up OnStep (e.g. latitude and longitude, horizon and overhead limits, and maybe backlash if you have it), but after that, it should be smooth.
If you do upgrade to 4.24, and you have a WiFi module, then you need to upgrade it with the SmartWebSever (SWS) too.
After a while I have been able to update the frimware and indi-server (on raspi and PC). But it doesn't make me meridian FLIP.
Are there any prerequisites that I must meet in order to do so?
Or, what would be the procedure to check that it makes me meridian flip?