This guide provides step-by-step instructions to resolve the "Invalid wkhtmltopdf version" error, commonly encountered in Frappe/ERPNext applications. Follow the steps below to install the correct version of wkhtmltopdf and ensure proper functionality.

Download the required version (0.12.6 with patched QT) using the following command:

wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.focal_amd64.deb

Install the downloaded .deb package using the following command:

sudo apt install ./wkhtmltox_0.12.6-1.focal_amd64.deb

If you encounter dependency issues during installation, run the following command to fix them:

sudo apt --fix-broken install

Then, reinstall the package:

sudo apt install ./wkhtmltox_0.12.6-1.focal_amd64.deb

Check the installed version of wkhtmltopdf to ensure it is correct:

wkhtmltopdf --version

The output should be:

wkhtmltopdf 0.12.6 (with patched qt)

Restart all services to apply the changes:

sudo supervisorctl restart all

Go to your Print Format in Frappe/ERPNext and try generating a PDF. The "Invalid wkhtmltopdf version" error should no longer appear.