Let me know if you'd like to see any changes to help with packaging.
If you are packaging around 3.1.1, versions older than 3.2.1 are incompatible with the recently released img2pdf 0.2.0; they require 0.1.5, and they do not enforce this dependency on their own. If you try to install any of them now, they will pull in img2pdf 0.1.5 and break. You would need to patch in img2pdf==0.1.5.
My current development branch adds a new dependency on cffi (libffi) to access leptonica (also a tesseract dependency), and automatic fixing of page rotation.
-JRB