base_requirements.txt of 12.0 in image version 5.1.0 causes errors

[whulshof]

In version 5.1.0 of the image definition the base_requirments.txt has much newer versions of python libs from the official odoo source requirements.txt.
This leads to strange errors. For instance PyPDF==1.27 leads to errors when printing.
I just want to understand: isn't it habit to follow the Odoo requirements?
If yes or no, why would we use much newer libs?

[whulshof]

I already found the reason: probably #149.
But dependencies are not flawless!