Maybe this is due to my being a newbie with using free viewflow (version 2.2.5). I am currently doing my first steps following along with the online documentation. I found that when running from viewflow.forms import ModelFormField the name ModelFormField could not be found. Indeed, dir(forms) confirmed that ModelFormField was missing while e.g. ModelForm was present in this module as expected. What went wrong? Was it my mistake or has ModelFormField been shifted to another module?
Here's what I found:

from viewflow import forms
dir(forms)

Out[6]:
['Caption',
 'Column',
 'FieldSet',
 'FormAjaxCompleteMixin',
 'FormDependentSelectMixin',
 'FormLayout',
 'FormSet',
 'Layout',
 'LayoutNode',
 'ModelForm',
 'Row',
 'Span',
 '__all__',
 '__builtins__',
 '__cached__',
 '__doc__',
 '__file__',
 '__loader__',
 '__name__',
 '__package__',
 '__path__',
 '__spec__',
 'renderers']