Apply patch to library for custom changes in Arduino IDE I wish to obtain unix epoch timestamps in millisecond precision. I am using an ESP32 along with DS3231 RTC breakout board from adafruit.

Apparently the Repository is not maintained often but I see a PR which overcomes the rollover for software timer and the developer provided a patch in the comment to use the unix timestamps in ms.

I went to the libraries folder where all the downloaded adafruit repos exist. But when I did  git status it mentions that the library download (from the library manager) is not a git repository.

I wan't to inculcate the changes to the RTClib library by using the patch provided. Should I just change the code directly via the Arduino IDE editor?
Save the patch to a file, put it in the directory holding the library,
open a terminal on that directory and type:

patch -p1 &lt; patchfile


You may have to install the "patch" utility if you don't have it yet. On
a Debian-like OS (I don't know for other OSes):

sudo apt install patch