dw2pdf based at mPDF 8.0.17

Version based at the 8.0 branch of mPDF. Higher has probably issues with php 7.4.

dw2pdf based on mPDF 7.0.3

Version based at the 7.0.3 release of mPDF. (this version supports PHP >=5.6 <7.3.0)

dw2pdf based on mPDF 6.0

Last version based at the 6.0 release of mPDF. (this version supports PHP < 7.0)

dw2pdf based at mPDF 5.7.4

Version based at the 5.7 branch of mPDF.
It serves as fallback for if the mPDF 6.0 has still some not foreseen issues.