Package-split upgrade path

[Sandro Mani]

Hello,

In python-pillow (the python imaging fork which replaced PIL in F19+), 
there is a module (ImageQt) which requires PyQt4, but that dependency is 
missing in python-pillow (and in python-imaging before). I don't really 
like adding PyQt4 as a dependency to the main package, since it pulls in 
lots of stuff. So, I'd go for creating a python-pillow-qt subpackage 
(albeit with just one file), and now am wondering about the upgrade 
path. From what I can see, there is just one package which uses the 
ImageQt module (pony, which actually looks to be rather unmaintained).
Question: What is the best way to proceed?

Thanks,
Sandro